. . "Range -20 to 60, Rail Material Steel, Rail Finish Precision Ground, For Use With FCP25351 Carriage PlatePrecision Ring Slides and CarriagesHepcoMotion PRT series for use in medical, packaging, filling line, or other applications requiring circular or curved (rotary) track motion.Steel ring slides with precision ground finish Hardened vee faces 52100 steel, 70 vee bearings, ground and polishedMore" . .