Discription for FOURIERS Shimano Oval XTR M9000 Chainring 34T 36T Teeth Mountain Bike MTB Chainwheel CR-DX9000-OV 36T Black: Narrow Wide chainrings for XTR M9000 11 speed With Narrow wide teeth, Teardrop holes, Wave Technology design.Oval shape design make the spincycle a lot smoother and is easier on legs while climbing. Adjust the oval in 3 position to increase its effect. The narrow-wide profile with our snug fit wave design have extreme chain retention qualities. Each tooth has additional CNC cut teardrop holes for better mud clearance.