UL Chainrings are the lightest 1x XC/Gravel chainrings on the market. Using the SL Chainring as the platform, we tweaked the arm design and strategically machined the chainring so that only minimal sacrifice was made in impact strength for large gains in weight reduction.UL Chainrings are -5mm (Boost) offset for use with XCX Race MTB cranks on Boost bikes. If you're installing XCX Race MTB Cranks onto a non-Boost (142mm) bike, please use SL Chainrings. ALL XCX Gravel applications will use the UL ring.Chain Reaction Updated M3 narrow-wide tooth profile eliminates chain noise, and decreases overall system wear.ChainlineTRS/LG1 Cranks: UL Chainring for SuperBoost chainline. SL Chainring for non-Boost and Boost chainline.XCX Mountain Cranks: UL Chainring for Boost chainline. SL Chainring for non-Boost chainline.XCX Gravel Cranks: UL Chainring for non-Boost chainline (142mm rear hub spacing)Compatibility 10/11/12 speed. Compatible with both Shimanoand SRAM12 speed drivetrains.CranksComp