Replaces the existing chainring and spider on 3-bolt BB30 cranks or SuperBoost chainline Features Drop-Stop tooth design to prevent unwanted chain drop Fits SRAM and other 3-bolt cranks Flat ring provides 50mm chainline on SRAM BB30 / PF30 short spindle (has 9.1mm drive side spacer) Drop-Stop B rings are compatible with 10/11/SRAM 12sp chain and Flat Top/Transmission chains. Not compatible with Shimano 12 speed Made in the USA from 7075-T6 aluminum alloy Compatible with SRAM FlatTop T-Type Chains, for use with SRAM Transmission and retaining your 3-bolt direct mount SRAM Eagle cranks. TECH SPECS ring type single (anti-chain drop) mount 3-bolt DM 0mm offset teeth 30t oval/round round color black