The NSB Variable Tooth Chainrings uses a ‘Thin-Thick’ variable tooth thickness mated with a standard chainring tooth profile to help retain the chain on the front ring during all types of riding. By increasing the tooth thickness on half of the ring’s teeth, the chain is given less room to move and virtually eliminates chain drop when running a single front chainring. Machined from solid 7075 T6 Aluminum. Anodized black with laser etched graphics. Variable tooth profiling ensures ultimate chain retention. Color: Black. Material: Aluminum. Chainring BCD: 88. Defined Color: Black. Ring Position/TYPE: Chain Retaining Single Ring. Drivetrain Speeds: 10. Drivetrain Speeds: 11. Tooth Count: 30.