Gears, Strombecker Pinion Gear set 9/10/12/14 tooth for 3/32" 0.0925" shaft. 48 Pitch. No. 8421 One each on factory card. Suitable for Pitmann, Kemtron and many other early .0925 pr 3/32" shaft slot car motors. They do not fit the .078" / 2mm shafts of Mabuchi and similar later motors. These are a close sliding fit on .0925 or 3/32". I believe they are intended to be fixed with solder, epoxy or locktight. Not a bad idea. All high performance slot cars use solder on gears. Press on gears are prone to distortion or motors damage when pressed and require special tools to remove. These only require heat. ;