Slide Ring 180 Degree Inside Dia 325.26 mm Outside Dia 367.74 mm Number of Rail Holes 6 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