Item No: 95597 Mini 4WD Special Project (Parts) HG 17mm All Aluminum Bearing Roller (Tapered Type) [These parts are useful for setting up and improving the performance of your machine] These 17mm diameter aluminum bearing rollers have a tapered (bowl-shaped) design that makes it easier for the machine to return to the course when it rides up on the course fence. The smooth rotation provided by the built-in 520 bearings is also attractive. In addition to the two rollers, two mounting screws and four aluminum spacers are also included. [Basic Specifications] Includes aluminum bearing rollers, two 2x8mm screws for mounting, and four roller spacers. [Usable Machines] Mini 4WD PRO, Mini 4WD cars (some bodies require modification) Item No: 95436 Mini 4WD Special Project (Parts) HG 19mm All Aluminum Bearing Roller (Tapered Type) [These parts are useful for improving the performance and setting up your machine] These 19mm diameter aluminum bearing rollers have a bowl (tapered) shape that makes it easier for the machine to return to the course when it rides up on the course fence. The smooth rotation provided by the built-in 520 bearings is also attractive. [Basic Specifications] Includes aluminum bearing rollers, two 2x8mm screws for mounting, and four roller spacers. [Usable Machines] Mini 4WD PRO, Mini 4WD cars (some chassis or bodies require modification) #Mini4WD #17mmRoller #19mmRoller #TaperedRoller