Heavy duty, 6.3mm thick, single chain rings.Great for 4X and DJ, or any other single ring set up.These rings are designed for the DMR Extype and CRISIS cranks and use tough splines, not a single drive bolt, to transfer the power.SplineDrive rings lock to the crank using a Shimano pattern lock ring and spring clip.The 36t and 38t rings are drilled to take the DMR Sideplate bashguardColour: Black