It uses the common 5/8″ bore (inside) diameter that matches up to the 5/8″ axle shafts on many popular models
This 10 tooth jackshaft sprocket is used with size #40, #41, and 420 chain found on many go-kart and mini bikes
Milled 7/16″ keyway slot For #40, #41, & 420 chain 5/8″ bore diam eter 1-3/4″ external diameter
This is known as a Type C sprocket
This jackshaft sprocket is not compatible with the Baja & Falcon mini bike