Mega-Clicks are the best training clicker in the world. I designed them to hug your finger snuggly so you can do other things with your hand and instantly return to the click. The "thumb bumper" lets you feel exactly where to push, without having to look or hunt for the end of the clicker to click. The "thumb bumper" is also a clip that allows you to clip the Mega Click to a pants pocket, shirt pocket, the neck of your t-shirt or just about any place else you want, when you aren't training. No more dangly-dangly on a wrist coil or fumbling to get the clicker settled in your hand. This thing is meant to last for years - and the elastic loop is replaceable if it ever breaks. ...........Gary Wilkes