Profile Design Universal Gap Cap: fits 1" or 1-1/8" steerer tubes, Aluminum Top Cap, Black $18,00 favorite_border Profile Design Gap Cap is a threadless plug that eliminates the need for a star-fangled nut; works with Carbon, Aluminum, and Steel steerers. Fits steerer Inner Diameter of 19.6 to 28 mm Color: Black See at Unlimitedbiking See all Component