Coupler and Plug Kit (28 Piece), Industrial Type D, 1/4 Inch NPT, Solid Brass Quick Connect Air Hose Fittings Set, with Sealant

I gave these couplers a 1 star rating only because I could not give them 0 stars.Out of the package these couplers look good. All brass as advertised and the machining looked excellent however they do not fit other M or D type of couplers. These couplers seal in a different and inferior manner than the couplers mfg in the USA. These couplers seal on end of the male plug and the USA couplers seal on the outside diameter of the male plug. I did check and they do work with each other. In other words the male plug did fit into the female coupler in the newly delivered package. I did not check for leakage as I knew I would be sending them back and did not want to use the pipe threads.This illustrates on of the main problems I have with Amazon. I carefully research the product to be purchased and do not click unless I am pretty sure it will work for me. These are probably made in China and are intended to resemble the ones made in the USA but they are not the same or interchangeable. These do not have any markings on any part of the plug or female. The quality is simply not the same. For example the machined hex faces, used to tighten the coupler to a pipe fitting are not nearly as wide. With soft brass this means that you are more likely to round off the hex nut corners. These couplers do not join as easily as USA couplers; it takes a great deal more force to couple the plug to the female connector on these than on my others.I think it would be helpful if the country of mfg is legibly identified in normal size font in the initial page of the product. Also helpful would be if the supplier is identified by name and location. In any case I may have to obtain the couplers I need from another source so I can be certain I get a reliable coupler of reasonable quality.

Two things:First, you must use teflon tape on the threads or you will get air leaks, tested three different ones and they all bled air without tape.Two; these are NOT universal, I have some auto and some industrial male ends on my tools, the female fittings only take industrial type fittings, not automotive.Otherwise, testing a few (taped) they seem okay.

Glad there were two male couplers in the order. Used one for my new Dewalt DW66-C1 siding nailer (did not come with a male coupler) and one for a water filter on the output of my pancake air compressor. The male threads fit both tools fine and no leaks using plumber's tape on the threads. The couplers are machined fine. Don't know about durability but am confident durability will be fine for my minimal use of my siding nailer. Would buy this again.

These couplers look great and at a great price but it ends there. They don't fit well even with their own couplers. You have to use three times the pressure to seat them and the headache isn't worth the effort. You get what you pay for... back they go to Amazon.

So if you have a 3/8” air hose it most probably has 1/4” threads and this connector will work to plug into a 1/4” compressor quick connect. I put this connector on with some Teflon tape and no leaks. So far so good. You get two connectors in the package. They are probably not high flow so if you have a demanding air tool you might want something better. For the me the value is worth it as it gets the job done.

These are very fine fittings and I much prefer brass to steel on these so there's not much more to say about them except high quality at an affordable price.

I had a cheaper one before but I think I am too careless and the valve started to leak. Got this one because I think this will def outlast the previous one. Much more sturdier. If you are more careful maybe you can get away with cheaper one

They work and don't leak. Solid brass means they should last and not corrode. Good price. Only suggestion is that the assortment should have more female fittings with female NPT sides instead of make NPT since you are mostly connecting those to hoses with make fittings on their ends.