Shimano four piston calipers, back from the dead. | Mountain Bike Reviews Forum
Shimano Deore M6120 Four-Piston Brakes
2 Piston vs 4 Piston Mountain Bike Brakes | Which Are Best For You?
Amazon.com: SHIMANO Deore XT BL-M8100/BR-M8120 Disc Brake and Lever - Front, Hydraulic, Post Mount, 4-Piston, Finned Metal Pads, Black : Sports & Outdoors