This is a 4" Skylite Wheel and Hub. FEATURES: Durable rubber tire Foam core Aluminum hub (wheel) Low bounce Rugged construction INCLUDES: One wheel REQUIRES: Installing on landing gear SPECS: Width: 1-3/8" (35mm) Diameter: 4" (102mm) Weight: 3.25oz (92g) COMMENTS: The secret behind Skylite"s toughness and light weight is a foam core surrounded by a durable rubber skin. Unlike hollow tires, the foam provides strength and bounce absorption. The outer rubber skin gives Skylites excellent wear characteristics. In addition to eliminating dead weight, Skylites have better balance and, unlike hollow tires, cannot lose pressure or go flat. tjt 061802 ir/kh