POWGE 8pcs GT2 Synchronous Pulley 20 teeth Bore 5mm 6.35mm 8mm + 5Meters width 9mm GT2 Open Belt 2GT pulley belt20Teeth 20T powge 8pcs 20 teeth gt2 timing pulley bore 5mm 6mm 6 35mm 8mm 5meters width 6mm gt2 synchronous 2gt belt 2gt 20teeth 20t