Promax Direct Mount Crank Spider - 104 BCD 4-Bolt SRAM 3-Bolt Mount Style For Use w/Promax CK-1 Carbon Cranks Only BLKPromax Direct Mount Crank Spider 104 BCD 4 Bolt SRAM 3 Bolt Mount Style For Use w Promax CK 1 Carbon Cranks Only Black. Specifically designed for the Promax CK 1 carbon cranks this aluminum spider adapter allows the use of a 104 BCD chainring with CK 1 cranks. High quality aluminum provides high strength at a low weight Specifically designed for use with Promax CK 1 carbon cranksets Utilizes SRAMs 3 bolt mount style to attach to crankarm (bolts sold