RIM AN (AM) 20 406x21 ACME UD CARBON TBLS DISC 28 BKUnidirectional carbon BMX rim designed for use with disc brake or as a brakeless front wheel. Full Toray T700 carbon fiber composite material. Drilled for both Presta and Schrader with included plug for unused valve hole. 220lb rider weight limit. Item Specifications: Size, 20in, Color, Carbon, Weight, 260g, Width OD, 28, Drill, 28, ERD, 390, Wall, Dbl, Valve, PV/SV, Model, Acme UD, Profile, 20, Tire Compatibility, Tubeless Compatible, ISO, 406, Width ID, 21, Brand, Alienation,.