The Shimano Dura-Ace FC-R1200 chainring uses hollow forged technology to provide a significant weight loss while giving increased rigidity. This guarantees the optimum power transfer. 

SHIMANO 2/11-speed chainring for Dura Ace FC-R1200 crankset and Dura Ace FC-R9100-P cranks with powermeter. While the inner chainring is made of anodised aluminium, the outer chainring has been hollow-formed (Hollowglide) from anodised aluminium and carbon fibre-reinforced composite to save weight. This results in first-class stiffness values and high durability.