-This chain breaker is for #25 #35 #40 #41 #50 320 410 415 420 520 525 530 roller chain, work with motorcycle bicycle go cart mini bike dirt bike motor bike chain etc. -Used for breaking chain, for repairing/replacing roller chain, to add/remove links of chain. -Material: high carbon steel, sturdy strong and solid bulit. -How to use: Squeeze the handles together to open the jaws. Place jaws around the link you want to break. Release the jaws. The pin should be over the pin in the chain. Turn the handle and the pin of the chain break will push the pin in the chain out -Important note: DO NOT push the pin all the way through the link or it will DESTROY the chain. Works great until the pin is about 1/2 way pushed out.