BlackStar H40SH21 - 40 Pitch QD Sprocket - 21 Tooth TL2012 "sku":"1185H050-D&D"

"sku":"1185H050-D&D"

so the Megadyne 17/C255 interchanges with Gates

"name":"Gates TP340H100 PowerGrip Twin Power Timing Belts"

3/A102 is a banded v-belt used on industrial drives - fans and blowers

"name":"D&D Global 12/C56 V-Belt - C Section

BlackStar H40SH21 - 40 Pitch QD Sprocket - 21 Tooth TL2012 "sku":"1185H050-D&D"The BlackStar H40SH21 is a 40 pitch QD roller chain sprocket with 21 teeth, precision manufactured from SAE 1045 steel with induction hardened teeth for extended wear life and features machine cut tooth profiles for smooth, reliable chain engagement. This sprocket requires a QD Type SH Bushing (sold separately). Specifications Part Number H40SH21 Chain Pitch 40 Number of Teeth 21 Maximum Bore 1" Bore Type QD Hub Style QD Bushing Required QD Type SH