

🖤 Compact power, limitless style — build boldly with Q300L!
The Cooler Master MasterBox Q300L is a compact yet highly versatile Micro-ATX/Mini-ITX case designed for professionals who demand modularity and superior cooling. Featuring a customizable I/O panel with six positions, support for large GPUs and CPU coolers, and a unique magnetic dust filter design, it balances functionality with a standout aesthetic. Its perforated all-around panels maximize airflow, while the transparent side panel proudly displays your build. Perfect for office or home setups, the Q300L delivers premium features in a budget-friendly, space-conscious package.

















| ASIN | B0785GRMPG |
| Best Sellers Rank | #4 in Computer Cases |
| Brand | Cooler Master |
| Color | Black |
| Customer Reviews | 4.5 4.5 out of 5 stars (13,724) |
| Date First Available | December 5, 2017 |
| Department | Computer Cases |
| Is Discontinued By Manufacturer | No |
| Item Dimensions LxWxH | 15.39 x 9.06 x 15 inches |
| Item Weight | 1.06 pounds |
| Item model number | MCB-Q300L-KANN-S00 |
| Manufacturer | Cooler Master |
| Number of USB 3.0 Ports | 2 |
| Product Dimensions | 15.39 x 9.06 x 15 inches |
| Series | Q300L |
| Wireless Type | 802.11a |
M**T
Good Budget friendly micro-atx case
Great value micro-atx case. Its cheap and works. Like the compact size and the fact it came with screws, spacers, ties and a fan. I like the magnetic dust filters concept however BEWARE of the very rough and pointed edges which could cut you while handling them. The power button on the side panel worked for me but could be a problem with other builds. I was barely able to fit two Thermalright TL-C14C 140mm fans in the front with the default front facing power button+LED panel layout, while managing the power/led/usb cables in between the two fans to the backpanel but it was a very tight fit. You can move the power panel to top bottom or rear if you have the space. My Thermaltake Smart 700W PSU blocked the bottom though. While the top was blocked the height and size of the Thermalright Phantom Spirit 120 SE Black CPU Cooler. And the rear was blocked by case fan and no real access for cable management through to the back panel. So I had to make the front faced orientation to work, which it did. All in all I am happy with the value of the product.
K**S
I am Pleased
awesome case great airflow and space the only thing is space for hdd or ssd you will have to make it work if you want a clean looking case and i wish this case had a cover for the psu but all in all i love the case and the airflow of this case definitely worth the money very solid built
I**L
Pretty Good
I was looking for a small mATX case to use with some older parts that I had in storage (I will list all the parts at the end for reference). So far it's worked great and I didn't really run into any major issues. I like how compact the case is and I was able to fit it under a small table. The computer is for light gaming and web browsing, so thermals have not been bad. Putting all the components together in the case was pretty straight forward. I found it a lot easier to work with than a small ITX or even a full ATX build. I didn't install any fancy or exotic parts (AIO/Water Cooling) and kept it simple, which I feel helped a lot. I like the dust filters that come with the case and the design on the filters give it a nice look. Since I am using a simple CPU (9400F), fan noise is non-existent since the processor doesn't generate a lot of heat. I'm using some Corsair RGB fans (x2 in front panel/x2 top of case), which look great and have them configured to silent in iCUE. There are a few issues so far with the case: 1) Stock outtake fan stops spinning randomly. I have it connected to the motherboard and have set the fan to full speed, but it does not fix the issue. I've also tried other fan headers on the board, but the fan continues to stop spinning. Not a big deal since a basic case fan is inexpensive, so I will be replacing it. 2) The Plexiglass can scratch easily if your not careful. I debated taking off the plastic film for this reason, but decided to remove it in the end. Glass would have been better, but for the price, you really can't complain. 3) Expansion slot covers are attached to the case, so removing them can be a little tricky. I ended up bending one of the slots a little bit, but was able to fix it by bending it back into place carefully. Finally, the only other thing that would have been nice is to have an all-in-one front panel connector. This would definitely help inexperienced builders to easily connect the front panel ports/power to the board without much struggle. Overall I'm happy with the case and do recommend it for anyone looking for an inexpensive mATX build that will look great. PC Specs: AsRock B365M Pro 4 Motherboard i5 9400F 8GB TeamGroup RAM 2133Mhz (two modules) RX 570 4GB TeamGroup SSD EVGA 650W Power Supply ATX (non-modular) ID Cooling Low-Profile CPU Fan (IS-47-XT) x4 Corsair SP120 RGB Fans with Commander Core
A**S
Best money you can spend on a cheap case
The good: Very good value for money. Case is well built despite being so cheap. I have a full length RTX 5060 Ti in this with room to spare for fans on the front of the case. Cable routing options are good. Plenty of space to run and tuck cables behind motherboard tray. I like the subtle grey/black color scheme. The bad: It's a little flimsy in spots, but it's 40 bucks and not gonna be moved a lot. Overall: If you want a basic, small, cheap but still very capable case for your next build, this is it. Will probably by another for my next build.
E**.
Stylish and Practical for a Budget Build
I’ve been using the Cooler Master Q300L for a few weeks now, and I really like it. First off, it looks great—clean design, tempered acrylic side panel shows off my build nicely. The magnetic dust filters are a lifesaver; keeping the inside clean is way easier than my last case. It’s compact but still roomy enough for a Micro-ATX board, a decent GPU, and a couple of extra fans. Cable management isn’t perfect, but it’s manageable if you take your time. For the price, this case gives you style, functionality, and solid airflow without breaking the bank. Definitely recommended for a budget-friendly build.
J**E
Solid choice for a small budget case
Rebuilt my htpc with some cannibalized parts from another pc upgrade. Mini-itx Asus ROG Strix with 2700x, 2070 super, Corsair 850x, M.2, and 2.5 SSD. Some things to note: PSU bracket is kind of odd, makes for a recessed ATX psu. Cable management is a bit challenging, front IO cables a bit shorter than they could be. Virtually zero space for CPU power, took me forever to get it plugged in. Airflow is good. I did 2 120mm intakes, you could fit 140's easily. Dust covers slide around very easily. Case screws and standoffs are in a tiny tear-open bag which underscores the low price of entry. Looks decent enough. I wouldn't buy it again, but it isn't at all bad. First time builders may want to choose something with a bit more QOL.
P**L
So this q300l case was released by cooler master in 2018 This Case was q500l 2019-2020 predecessor This case has holes in top, front and bottom I had 5 fan laptop cooler on which this Case is sitting right now, my laptop had fan issues so now it's used for PC case cooling I have attached 2 arctic fans 140mm 1600rpm and 120mm ,1200rpm in front for intake 2 coolermaster fans one for exhaust (xtraflow 1500rpm) backcand one for top ( 200-1000 rpm) 1 circle fan (1000-1200) rpm My PC temp with just one exhaust fan was around 45-55 during normal usage and CPU temp was around 64-74 degrees on normal to heavy load and gpu temps were 50 - 60 degrees CPU fan was spinning at 1500 rpm max After bumping up AMD wraith Cooler fan to max fan speed of 2600 rpm in bios settings, my CPU temps went down to 50 degrees. After installing all the fans, My case temps are 36-39 degrees My CPU temp is at 42 degrees normal and at 57 on load. If your buying this case get at least 2-4 fans You can 140mm fans or radiator in the front only On top only 120mm can be attached properly I could be wrong depends on brand and size of 140mm fan My arctic fan screw holes weren't able to match on top of the case. The magnetic dust filter on top and front can be cleaned easily. The side panel is acrylic, fingerprint magnet. 2 USB 3.0 jacks in front Mic and headphones Jack with HD audio but can only do 5.1 channel not 7.1. I had to attach my 7.1 channel headphone in the back Cable management very good Lot of spaces in the back. If you have radiator then your CPU temps will get better than mine . This case should cost around 3500 rupees But I had no choice but pay up 4500 rupees Cuz it I needed it urgently. This pandemic has really screwed PC enthusiast when it comes to pricing of PC components. 4/5 My PC specs AMD 1300X 3.8ghz (2018) Sapphire pulse RX580 8gb OC lite (2020) 😑 Ballistix red 16gb (2020)😑 Cooler master 550 mwe psu (2018) Acer vgo monitor 144hz LG monitor 75hz
K**E
1) Cable management that does not suck, that's a big advantage 2) Can be placed under the monitor on the desktop, rubber pieces on the long side 3) With 3 PWM-driven chassis coolers it is a silent beauty 4) Overclocked graphics card temperature is below 65°, that's very nice airflow 5) The side panel is acrylic, not glass, which is so so, but pretty fine for a budget setup 6) Buttons and USBs can be rebased at any side, but I just kept them as-is 7) Very careful and lovely use manual, showing all necessary addons for different setups 8) Loved the included rubber pieces for easy placing of the SSDs Would definitely recommend it!
D**L
Goede kast met aardig wat mogelijkheden! Had zelf een kast nodig die niet te veel ruimte innam en niet al te duur was. Ik ben positief verrast.
D**A
O gabinete é ótimo e super bonito, o que mais me chamou atenção dele foi o design super compacto e a versatilidade de usar, mas apenas de ser bonito, ele tem os seus defeitos. O acrílico é super fácil de arranhar, enquanto eu estava mudando as peças do meu antigo gabinete para esse, eu deixei o acrílico encima da minha cama com todo o cuidado do mundo, porém, quando eu fui fechar o gabinete com o acrílico, eu vi um pequeno arranhão no canto inferior direito, de início eu não dei muita importância, mas com o reflexo da lâmpada do meu quarto eu achei vários e vários pequenos arranhões que só podem ser vistos na luz, eu simplesmente não entendi o que causou aquilo, já que eu tive o máximo de cuidado possível, mas para quem vai comprar esse gabinete, cuidem do acrílico! E de resto ele me agradou muito, acho incrível como a Cooler Master consegue fazer excelentes gabinetes com preços incríveis. Apesar de ser um gabinete M-ATX, tem como você colocar até 6 fans de 120mm nele que eu achei super top e bacana. Recomendo d+.
C**N
Ottimo case, non pensavo che spendendo poco più di 60 euro potessi avere un gioiellino simile, le dimensioni sono ridotte ma l'airflow è eccellente a patto di acquistare qualche ventola aggiuntiva in quanto abbiamo solo una 120 sul posteriore che fa comunque egregiamente il suo dovere. Supporta schede madri mini-itx e micro-atx (il mio caso) e dentro ci sta tutto. Come si vede dalla foto ho installato una GPU bella grossa, una asus dual 6700xt lunga 30 cm e un dissipatore bello generoso, un cooler master 212 alto 16 cm (ci va a pelo quindi controllate bene l'altezza del vostro dissi prima dell'acquisto).Il cable management è abbastanza agevole soprattutto in relazione alle dimensioni ridotte. Per quanto riguarda la PSU ci va un normalissimo ATX mentre per i dischi entrano tranquillamente due ssd da 2.5" e un HD da 3.5" ma il suo posizionamento sul fianco destro del case non mi convince appieno per motivi di mancanza di areazione. Due filtri a calamita con una bella trama a nido d'ape sono posti sul front e sul top mentre un terzo e posto alla base. L'unica pecca a mio avvisono è la "placchetta" dei pulsanti di accensione/reset e delle prese usb che sembra essere un pò fragilino ma posizionabile su tutti e 4 i lati del pannello.Il pannello laterale è in plastica, fosse stato in vetro temperato sarebbe stato veramente il top anche se a questo prezzo forse sarebbe stato pretendere troppo. Se cercate un case bello esteticamente esteticamente e curato nei dettagli non posso che consigliarlo.
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