AB Premium Shimano 110/4 bcd compatible ROUND chainrings are designed for new type of Shimano cranks Dura-Ace 9100 & Ultegra 8000 & 105 R7000. Compatible with Di2. These are the finest aftermarket Round chainrings in terms of shifting, design and manufacturing quality. IMPORTANT: These chainrings are also Backwards compatible for 9000, 6800 and lower groups. Mounting tabs are a little different in appearance from older model, but with use of dedicated 9000 or 6800 Bolt covers they look perfect. It is especially important for 53/39 combination as we only provide it under this category but can be retrofitted to 9000 and 6800 cranks.