Mellow 3d Printer Gt2 Open Timing Belt Pulley 20 Teeth Bore 5mm For Width 6mm/9mm/10mm/12mm Gt2 Synchronous Belt 2gt 20teeth 20t - 3d Printer Parts & Accessories - AliExpress
Geoff's Y-Axis Idler Pulley & Gear for Solidoodle2 - all 3D printed by geoff_cohen - Thingiverse
Mellow 1set 3d Printers Parts Vzbot Gt2 Idler Kit Aluminium Timing Pulley 20 Tooth Wheel Bore 5mm For 2gt Gates Timing Belt 6mm - 3d Printer Parts & Accessories - AliExpress
Delta printer belts and 16 tooth pulleys | Duet3D Forum