Lower chainring bash protection without upper chain retention Reinforced nylon bash guard and a back plate cut from 8mm thick 7075-T6 aluminum Includes 3 different sizes of bash plate for compatibility with chainrings from 28-36t - Oval chainring and Boost compatible 2.5mm chainline adjustment Designed for frames with 2 ISCG05 tabs only (Evil, Rocky Mountain, etc). Should not be used on frames with 3 ISCG05 tabs