I own quite a few nunchakus, and Ive purchased a whole bunch from this store. I've been 100% satisfied with all of them except the LED chucks. They are trash. My first set came broken, only one chuck would light up. Then I was sent a new pair to replace the old one and guess what? Same exact problem. Apparently this product is easily damaged and doesn't seem to last very long. The LED light itself is poor and weak. It is a tiny bulb inside the ball bearing that is so fragile, it will probably break if you're not experienced and continuously drop the chuck on the ground.
It hardly lights up the chuck at all either.
The light is more of a faded light red tone rather than the powerful deep red LED that you would come to expect with all the LED keychains out there nowadays. Even the plastic lightsabers look cooler than this product.

Not only that but since the button to turn the light on and off is on the top of the chuck where the chain attaches to the ball bearing, it accidentally turns on and off while you spin it. This is frustrating and defeats the purpose of having LED chucks. The ball bearing itself has 2 screws on each side which interfere if you're trying to do cool wrist flips and tricks. I sent back both LED chucks for a full refund and highly recommend AGAINST purchasing this product.

You are better off making your own small glow chucks out of glow sticks, a small chain and key rings. I have made quite a few and they're great for parties and fun in the dark.
Hope this review helps.