The RaceFace ERA Direct Mount Wide CINCH SHI12 Chainring is designed for use with Shimano 12-Speed HG+ chains. RaceFace bonded a carbon fiber spider with stainless steel teeth and a premium 7075 aluminum CINCH interface to offer a chainring that is expected to last 5 times longer than a typical alloy chainring. ERA is s chainring without compromise.Carbon fiber spider compressed and co-molded using the same process we developed for ERA carbon cranksTried tested and proven CINCH mount uses premium 7075 aluminum is lightweight durable and with CINCH it&';s easy to swap out ring sizesStainless steel teeth are stronger and harder than titanium with a wear life five times that of aluminumProvides a 55mm chainline with RF136 crank spindleDesigned for Shimano 12-speed HG+ chains only TECH SPECS table{border-collapse:collapse;width:100%;} td{text-align:left;padding:8px;font-weight:350;} tr:nth-child(even){background-color:#f2f2f2} th{background-color:#eb212e;color:white;text-align:left;padding:8px;} .desc .specs-heading{font-size:24px;font-weight:600;padding-top:35px;border-top:3px solid #f0f0f0;display:inline-block;border-bottom:4px solid #eb212e;width:142px;margin:0;} Tooth Count 30 Drivetrain Speeds 12 Round or Oval Round Material Aluminum Color Black Defined Color Black Direct Mount Type Direct Mount CINCH Chain Compatibility Shimano 12-Speed HG+ Size 30T