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 4.522 in Outside Diameter 1.375 in Finished Bore FEATURES Conforms to ANSI B29.1-1975 standards SPECIFICATIONS CHAIN NO. 50 MARTIN NO. 50BS21 MATERIAL Steel SINGLE STRAND TOOTH THICKNESS 0.343 in KEYWAY w/Keyway Set Screw WIDTH ACROSS TEETH 0.343 in SPROCKET STYLE B BORE TYPE Bored to Size HUB LENGTH THRU 0.657 in NO. OF TEETH 21 HARDENED TEETH Without Hardened Teeth CALIPER DIAMETER 3.7817 in HUB PROJECTION 0.66 in FINISHED BORE 1 3/8 in KEYWAY SIZE 5/16 x 5/32 PITCH DIAMETER 4.193 in INCH/METRIC Inch OUTSIDE DIA. [MIN] 4.5220 in HUB DIA. 3 in CHAIN PITCH 5/8 in LENGTH THROUGH BORE 1 in NO. OF SCREWS 1 NO. OF STRANDS ACROSS 1 PITCH DIAMETER [MIN] 4.193 in SET SCREW SIZE 5/16-18 X 5/16 OUTSIDE DIA. 4.5220 in WEIGHT 2.03 LB EAN OR UPC 697950011813