From old stock. Had some rust and staining and I cleaned it up a bit. Has never been on a machine.Buyer will receive the sprocket shown. 40 Chain Number 1 Strand 21 Teeth Without Hardened Teeth B Sprocket Style DESCRIPTION Maximum bores shown will accommodate standard keyseat and setscrew over keyseat. Slightly larger bores are possible with no keyseat, shallow keyseat, or setscrew at an angle to keyseat. FEATURES Tolerances meet or exceed ANSI standards Manufactured of high carbon steel Precise machining and processes ensure consistent finish and high quality Bores are concentric to pitch line, minimizing run out SPECIFICATIONS CHAIN PITCH 1/2 in HUB DIA. 2 3/4 in WIDTH ACROSS TEETH 0.28 in INCH/METRIC Inch HARDENED TEETH Without Hardened Teeth OUTSIDE DIA. [MIN] 3.6200 in NO. OF TEETH 21 CHAIN NO. 40 OUTSIDE DIA. 3.6200 in NO. OF STRANDS ACROSS 1 MATERIAL Steel CALIPER DIAMETER 3.03 in MARTIN NO. 40B21 KEYWAY No Keyway or Setscrew HUB LENGTH THRU 0.716 in BORE RANGE [MAX] 1.8800 in PITCH DIAMETER [MIN] 3.350 in SERIES B SPROCKET STYLE B BORE RANGE [MIN] 5/8 in BORE TYPE Reborable CONSTRUCTION Solid LENGTH THROUGH BORE 1 in BORE STYLE Minimum Bore PITCH DIAMETER 3.350 in WEIGHT 1.73 LB EAN OR UPC 697950005096