This is the Extra Hard 5mm .8 Module 18 Tooth Brushless Motor Pinion Gear from Robinson Racing. FEATURES: Extra Hard Construction, gun in color Fits motors with shaft diameter of 5mm Will also work on stock motors using the a reducer sleeve (RRPC1200) INCLUDES: One 5mm .8 Module 18T Pinion Gear One 4x4mm set screw (RRPC1201) REQUIRES: Installation onto the motor shaft SPECS: Length: 0.47" (12mm) Mounting hole diameter: 5mm COMMENTS: Also available is a: 12 tooth pinion (RRPC8712) 20 tooth pinion (RRPC8720) 13 tooth pinion (RRPC8713) 21 tooth pinion (RRPC8721) 14 tooth pinion (RRPC8714) 22 tooth pinion (RRPC8722) 15 tooth pinion (RRPC8715) 23 tooth pinion (RRPC8723) 16 tooth pinion (RRPC8716) 24 tooth pinion (RRPC8724) 17 tooth pinion (RRPC8717) 25 tooth pinion (RRPC8725) 19 tooth pinion (RRPC8719) cnh 6/21/08 ir/jxs