Keep your chain where it belongs, on the rings! Mounts on the seat tube and prevents the chain from coming off to the inside. Adjustable hose-type clamp fits 1 1/8" to 1 3/8 seat tubes. Great for cyclo-cross or any bike with a persnickety front derailleur.
Simple and effective way to alleviate the dreaded chain drop.
This product works perfectly. My chain has not come since it was installed.