Water resistant saddle cover to protect your saddle from rain. Made of nylon. A drawstring around the lower edge keeps the cover in place. Please don't use this while riding, just put it on if you need to leave the bike out where it will be exposed to the elements. You might want to grab a tin of saddle conditioner too. This is the medium cover which will fit narrower saddles such as Brooks B17, Flyer, Team Pro, etc. but not wider saddles like the B67.