Auto-Start NSD Rainbow Lit Spinner Gyro Ball – Up to 15,000 RPM Premium hand strengthener and wrist exerciser for grip strength training, forearm workout, and pain relief; durable and portable

I love this. It is essentially a gyroscope. The ball contains an inner ball which is weighted and rests on gimbals You don't need a string to start it. It has an internal spring. Once wound up, the ball beings to turn, By rotating your wrist in a particular way best learned by viewing a video, the speed of the ball will increase. As the ball increases in speed, the laws of physics dictate that attempting to rotate its spin axis by applying torque, the gyroscope will try and rotate at right angles to the force you apply. This is called gyroscopic procession. This is why gyroscopes are used in navigational systems on earth and in space. They want to stay in position and by so doing, there is an initial frame of reference.As the speed of the gyroscope increases it gets more and more difficult, that is you need to apply more force to get the ball to spin faster. As a result you are putting stress on the muscles of the wrist and forearm...exerciser. It is a novel way to strengthen your arm and is just plain fun. I recommend you also purchase the NSD Power SM-02 Precision Multi-function Speedometer so you can measure how fast you can get the gyroscope to spin.

Bought this to help exercise my wrist and forearm after an RSI scare.Not gonna lie. I spent a few hours figuring out how exactly to spin this, until enough videos made me realize that I had to spin it slower and not faster - I was spinning too fast to stay in sync.The key for me was the wrist motion (can't really explain it, but you should be rotating it horizontally and tilting it on the vertical axis) as well as trying to "feel" it sync.Once I got it working, I couldn't resist using it even when tired - there's just something about the flashing lights and the whirling and the resistance and the motion that just feels rewarding. I'm pretty sure the flashing lights are a way of gamifying it - which is a really good thing if it gets you do something that helps you.I bought the auto start model because I knew I would lose the rip-cord of the other models, and while I didn't get a counter, after a week with this I decided to get one to keep track of how well I'm doing with it.Did it cure my RSI? Too early to tell.Is it a great exercise? HECK YEAH

Maybe my personal incompetence, I find mine is easier to start from left hand and accelerate than my right hand. From the pictures, there seem to be 2 versions.I am right handed, but I exercise both hands, its a none issue. But I will always be wondering.

I ordered this for a buddy of mine who has been undergoing treatment (chemo and radiation) for a brain tumor. He's not doing well at all and has lost a great deal of strength in is hands, arms and wrists. This device is actually helping him, which is all I could have hoped for. This nice thing about this device is that it works well at even slow speeds. You don't have to crank it up very high to get some resistance, which is perfect for my old buddy (he's 86 years old).I highly recommend the NSD Roll 'N Spin if you want or need a minimal fatigue hand and wrist workout, whether you're recovering from an injury or you just need to build up your strength slowly/gradually. You CAN speed it up and get a workout if want to, but at lower speeds it perfect for someone who just can't handle heavy loads. HIGHLY recommended.

I love this thing. It's quite unassuming just looking at it, but it's a heck of a workout. I make medieval armor as a hobby so my grip strength is pretty good. After 5 minutes with this thing, I knew exactly which muscles I have not been using. A friend had the string start version which is were I learned about this little gyro centrifugal gadget. I got the auto start version and it's definitely worth the few extra bucks. No worrying about loosing the string and the startup speed from the spring is double that of what you can achieve with the string with less hassle. As for the construction, the core has been machine balanced and the ratchet mechanism is all metal for a long life. They also make a higher end version that's double the pounds of resistance. Definitely a future purchase. I would recommend starting with this one unless you are a body builder.

I'm the only one I've met in person that can get it to work, but it's a great workout. Multiple people have asked what I've changed in my workout, because I'm definitely getting larger arms.I thought about knocking a star off because it is pretty fragile. I dropped it on the concrete in my basement and it doesn't seem to want to go, anymore. But.. I turned around and ordered the $100 titan immediately after without regrets, and it was my fault it fell, so I'm not going to hold it against them.

This spinner worked well for about a day, at which point I disassembled it to install the spin counter attachment. Once I got it apart I realized that the internal mechanism was slightly different than every other guide I could find online; it included a separate white plastic ring which no other model seems to have. Long story short, I can't seem to figure out how to get it put back together in a way that will actually engage the gyroscope.I looked online for a guide and could find nothing. I used their customer support form, which failed to work with an error about trying again several times. I called their customer support number, which rang until it reached a voicemail that hadn't been set up. I can not seem to make contact with NSD in any way to get my spinner working again.Poor form.

I bought this because a friend had a similar model. This one is good for the money, and is great for getting started with these to see if you like them before buying something better made. I used it for a few weeks before the bearings started to wear, and you can really hear things starting to wear out inside.It still works, but needs a bit more to get it going than it did before. I wish I would have gotten the one with the counter on it instead, cause I'm a fan of seeing stats on things.