Slide Ring Full Ring Inside Dia 114.63 mm Outside Dia 139.37 mm Number of Rail Holes 8 Mounting Hole Center to Center 127 mm Mounting Hole Size 3.7 mm Thread Size M3 Screw Type Socket Head Cap Screw Temp Range -20 to 60 Rail Material Steel Rail Finish Precision Ground For Use With FCP12127 Carriage Plate