Slide Ring Full Ring Inside Dia 325.26 mm Outside Dia 367.74 mm Number of Rail Holes 12 Mounting Hole Center to Center 351 mm Mounting Hole Size 5.5 mm Thread Size M5 Screw Type Socket Head Cap Screw Temp Range -20 to 60 Rail Material Steel Rail Finish Precision Ground For Use With FCP25351 Carriage Plate