Torx T30 bolt for greater reliability with standard slotted nut \n CNC machined 7075 with type II anodizing \n Long fits 110/4 &110/5 BCD for outer+inner ROAD oval chainrings, 104BCD oval 26/28/32T, 64BCD round 26/28/30T, 94BCD oval 30/32/34T \n Short fits 104BCD oval 34/36T, 110/4 and 110/5 CX oval 38T, and 104BCD round 32/34/36/38T \n For XT M8000 and XTR M9000 use original Shimano bolts \n For Road inner oval chainring only with original round outer, use original bolts