FSA DH Alloy CNC Chainring FSA 4 bolt precision CNC machined, AL7075/T6 alloy, 3mm thick chainrings with recessed chainring bolts from either side. FSA DH Alloy CNC Chainring Features: Sizes – 104mm x 34, 36, 38, 40, 42 T 4 bolt, 104mm BCD 3mm thick Black anodized with laser logos Single chainring use for 8 or 9 speed systems Buy FSA DH Alloy CNC Chainring from Chain Reaction Cycles, the world’s largest online bicycle store.