... Connecting Link :Color: black,blue,or other optionalSize: 35,40,2040,41,50,2050,50H,60,60H,80,80H,100,120...ROLLERSolid ... RollerMaterial 1035,1045 or 1050Through harden with surface and core 40 ... Sides )Material 1045 or 1050Through harden with surface and core 39-45HRCShot peening per the spec roller chain connecting link