This is the latest (Batch 6) version 5th gear cog for the Cyclone 5 Speed gearboxes. We have changed manufacturer and all Cyclone products, including complete gearboxes and spare parts, are made from the latest specification materials and vastly improved manufacturing methods giving greater strength and quieter running. This fifth gear cog can be used with all Batch 1 - Batch 4 versions marked 'DRT' and all subsequent RLC produced Batch 5 - Batch 6 versions, marked 'PZ'.