Our new Direct Mount Chainrings for SRAM 8-Bolt Mountain Cranks are optimized for the new SRAM Transmission mountain groupsets and T-Type chains. These are for folks who have the latest SRAM T-Type Transmission groupset that want a different chainring size beyond stock offering or upgrade to a Made In USA option with an optimized tooth profile for better performance. The 3mm offset is for SRAM MTB cranks with DUB WIDE spindles that are already at the 55mm chainline required for SRAM T-Type Transmission groupsets.