Description Sprocket diameter with tracks: 2.75" Designed to be used back to back for a dual sprocket configuration The Lynxmotion Track Sprocket - 6 Tooth (Pair) SPRK-01 work with Lynxmotion HUB-11 Passive Idler Hub (pair) (RB-Lyn-220), Lynxmotion HUB-02 Universal Hub - 6mm (pair) (RB-Lyn-17) and Lynxmotion HUB-03 Universal Hub - 4mm (pair) (RB-Lyn-18) View more Links Web Site Video