Oh, you can get differant types, the first basic ones that were just a ball, then the more you pay the more you get, mine has lights, more lights come on the faster it is going, a screen to tell you how many reps per min and other functions like 60 second timer to see how fast you can get it going in 60 secs...

Did you ever notice any forearm or grip improvements from using it?

nvm bro thats not the one i had it didnt keep score

Yeah exactly bro! My high score is 10675. You?

haha yea thats the one! I pulled it with a red string to start it LOL