Not just fast and reliable front shifts, but silent running across the whole cassette. The RED AXS front derailleur uses Yaw technology with electronic trim to ensure the fastest possible shift while eliminating chain rub in all combinations, with the easiest setup around, thanks to a brilliant new tool. AXS enabled for easy wireless setup, monitoring, personalization, and reliability Refined cage shape results in faster and more accurate front shifts Easy setup with included tool Compatible with 46/33T, 48/35T, 50/37T, 52/39T, 54/41T, and 56/43T AA57chainring combos Battery not included SRAM Model ID: FD-RED-E-E1.