Premium Shimano 110/4 bcd compatible oval chainrings are designed for Dura-Ace 9100 and Ultegra 8000, but can also be retrofitted to 9000 and 6800 series cranks Expertly CNC machined from 7075 aluminum and type II anodized for a long lasting contruction and finish Ramps on big rings are specially configured for combinations: 50/34, 52/36, 52/38, 53/39T - other combinations will work but may require more derailleur adjustment *30T can only work with 46T and special bolt set 46/30. (bolts included with small ring) *32T can only work with 48T and special bolt set 48/32. (bolts included with small ring) Due to special mounting construction, aesthetic bolt covers are not offered for these designs 110mm 4-bolt 48T 7075AL Black 10/11/12sp Standard