This is the defender xc1xc11 29er mudguard set these are 29 wheel specific mudguards the xc1 is a super light two piece moto inspired front fender that attaches to the suspension fork lowers for a closer fit to the tire and excellent mudspray protection a precision clamp assembly secures the fender to the forks lower legs and a special safety feature allows it to disengage if a large obstruction enters the wheel the two piece qr bolt on fork attachment fits 36 485 mm diameter fork