Star mount fits most 28mm outrunners. Fits our Maytech 2830 and 2836 series motors and most other imported motors in this size class using similar looking star mounts. Motor bolt holes are .625" (15.8mm) on center for one pair and .730" (18.54mm) on center for the other pair. Outside holes are 1.375" (35mm) on center. 1/8" Thickness, overall OD 1.870" (47.5mm) 3D printed solid ABS part. Center hole .400" (10mm).