USAmade Sharktooth Narrow Wide 94mm BCD Mountain chainring, Black Anodized Finish with Teflon coated surface treatment, 4-Bolt, threaded for a standard M8x0.75 chainring bolt- recommend 8 mm bolts, aircraft aluminum alloy, Alternating "Thick-Thin" tooth profile for chain retention- the latest technology, Sharktooth Series - No Chain Drop tooth profile for all conditions chain retention, Greater built-in offset for chain clearance on most popular cranks, Designed to use 3/32", 8,9,10 and 11-speed chains. - Made in the U.S.A.