Check the listing for details. Wolf Tooth 104 BCD Chainrings Black 40T Drop-Stop B. Condition: New. Listed at 74.95 USD. 104 BCD is the most common bolt pattern on double and triple cranksets and happens to be the first product ever made by Wolf Tooth Components. This chainring started it all for us. The Drop-Stop tooth design is the best performing and longest lasting wide/narrow chainrings on the market. . Fits any 104 BCD crankset. Drop-Stop technology. On Wolf Tooth s patented wide/narrow chainring, the wide side of the tooth has maximum contact on the drive side which spreads the load and improves chainring life. The narrow side allows clearance for mud and debris which reduces friction. Alternating wide/narrow tooth pattern prevents chain derailment. Compatibility Fits any 104 BCD crankset. Designed to meet the requirements for E-bike use. Chainring Bolts: All tooth sizes require 1x bolts that are 6mm.