These FLH billet fender spacers are designed to work with Arlen Ness "Hot Legs" billet lower legs, American Suspension " Bagger Legs" billet lower legs, or stock Harley Davidson 41MM FLH & FLT lower legs, not FX or XL legs. The 1-1/4" thick fender spacers can be used with a 6-3/8" wide custom front fender. The 1.0" thick fender spacers can be used with a 6" wide custom front fender. The 0.8125" thick fender spacers can be used with a 5-1/2" wide custom front fender.