The Blackburn Mag 9 Magnetic Resistence Trainer is a bike trainer for indoor sessions. No assembly required, except attaching your bike, and it Fits a range of wheel sizes from 26"x1" to 29"x2.3". The 9 levels of resistance gives you plenty to work with, whether you're looking for a hard workout sesh or just a quick and easy ride. Or get a little of both worlds, as the handlebar remote changes the levels as you prefer. Features of the Blackburn Mag 9 Magnetic Resistence Trainer Bike installation is simple and works with many wheels sizes from 26 x 1 in. to 29 x 2.3 in. Nine resistance settings across a broad range of levels QR skewer included to minimize damage or scratching of original QR No assembly required