This set includes a double helical/spur gear, a double helical gear and a single helical gear. 1/4" center holes. Double helical/spur gear has a 2" diameter (58 teeth) thermoplastic helical gear with a 3/4" diameter (19 teeth) metal spur gear attached. Assembly length is 2-1/2". Double thermoplastic helical gear is 1-1/4" diameter (35 teeth) and the attached helical gear is 1" diameter (28 teeth). Single gear is also thermoplastic and 1-1/4" diameter with 35 teeth.
