DMR Blade Direct Mount Chainring - 34T Boost 12-SpeedDMR Blade Direct Mount Chainring 34T Boost 12 Speed. The Blade chainring is now 10 11 and 12 speed compatible. Manufactured from stiff 4mm wide 7075 T6 Aluminum maintaining direct power transfer this MTB direct mount chainring has a wide narrow tooth design for ultimate chain retention and when combined with a clutch mech no chain device is needed. Wide Narrow tooth design with direct mount interface Fits Shimano KMC SRAM 10 11 and 12 speed chains