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. 50 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 HARDENED TEETH Without Hardened Teeth PITCH DIAMETER [MIN] 4.190 in SPROCKET STYLE B CONSTRUCTION Solid PITCH DIAMETER 4.190 in LENGTH THROUGH BORE 1 in SERIES B NO. OF STRANDS ACROSS 1 KEYWAY No Keyway or Setscrew CHAIN PITCH 5/8 in MARTIN NO. 50B21 BORE RANGE [MAX] 2 in BORE RANGE [MIN] 3/4 in HUB DIA. 3 in BORE STYLE Minimum Bore OUTSIDE DIA. 4.5200 in OUTSIDE DIA. [MIN] 4.5200 in INCH/METRIC Inch CALIPER DIAMETER 3.78 in BORE TYPE Reborable WIDTH ACROSS TEETH 0.34 in HUB LENGTH THRU 0.657 in NO. OF TEETH 21 MATERIAL Steel CHAIN NO. 50 WEIGHT 2.4 LB EAN OR UPC 697950011738