Type:Round Chainring / Single Chainring.BCD:107.Color:Black.Hardness:150 HB.Thickness:4mm.Material:7075-T651 Aluminum, from Aleris USA.Process:CNC, anodized surface.Suitable:SRAM RIVAL AXS 4-arm.(Not compatible with FORCE AXS - For this model see reference ST-107 / ST-107OV).Speeds:For SRAM 12 speed Flat top / T-TYPE chain.Note:If the chainring uses a SHIMANO 12-speed chain, replace the original buckle with a KMC 12-speed buckle.38 teeth - 78 grams