SRAM RED Flattop Chain - 12-Speed 120 Links Flattop PowerLock Silver D1. 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 durabilityCompatible only with eTap AXS rear derailleursHard Chrome plated inner and outer plates allow for faster and more precise shiftsHollowPin construction provides increased strength and efficiencyRequires Flattop Powerlock chain connector