The SRAM RED AXS 12-speed Flattop Chain features a unique link shape that allows the chain to be narrower and lighter while increasing strength and providing more tolerance between cogs. Flattop technology enables a narrower chain with quieter operation and increased strength and durability. Compatible only with eTap AXS rear derailleurs. Hard Chrome plated inner and outer plates allow for faster and more precise shifts. HollowPin construction provides increased strength and efficiency. Requires Flattop Powerlock chain connector.