These high quality billet aluminium pulleys are designed to couple to stepper motors to provide linear motion control. 
 
They feature 2 grub screws for fastening to your stepper motor shaft and have a GT3 tooth pattern for sturdier engagement in High torque applications.
 
Specifications
Bore Size: 6.35mm
Teeth: 20T
Belt type: GT3
Belt width: 6.9mm(max)