PMW Applications: 6"SRT* Xp = X-ped* SXp = Super X-ped* SSKU = Super Sport Upgrade KitSpecifications:* Not gritted. "smooth"* Diameter with No grit = .624"* Lenght = 2.00"* Includes: Drive spindle; no grit (Xp,SXp,GXp,GSp) [part# 1013X]* Includes: spindle mount bolt; M6x50 SHCS [part# 1016]* 6"SRT = 6" Solid Rubber Tire "products".