Wolf Tooth 120 BCD Chainring - 36t, 120 BCD, 4-Bolt, Drop-Stop, BlackDesigned as a direct replacement for cranks or 4 bolt spider utilizing a 120 BCD. These rings will allow you to convert your 120 BCD crankset, like the SRAM XX and others, to a 1x application. They feature Wolf Tooth's proprietary mud clearing Drop Stop tooth profile design. Product Details: Compatible with all 10 , 11 , and 12 speed chains, with the exception of Shimano 12 speed chains Drop Stop chainrings are designed for use with 1x9, 1x10, 1x11