John Deere Original Equipment Spur Gear - M111151.
This part fits;

12PB,12PC,12SB,14PB,14PZ,14SB,14SC,14SE,14SZ & 14SX 21-In. Mowers (Silver)(SN 010001 - )

14PT and 14ST Walk-Behind Mowers

21-Inch Walk-Behind Mowers

JA62 21-Inch Walk-Behind Mower

JA65 21-Inch Walk-Behind Mower

JE75 21-Inch Walk-Behind Mowers

JS61 21-Inch Walk-Behind Mower

JS63 and JS63C Home Depot 21-Inch Walk-Behind Mowers

JS63, JS63C, JS63E 21-Inch Walk-Behind Mower

JX75 21-Inch Walk-Behind Mowers

SABRE 21-Inch (14PS, 14SS) Walk-Behind Mowers 

SABRE 21-Inch (M10, M21, M23) Walk-Behind Mowers

Scotts SP6211/SP6213 21-Inch Walk-Behind Mower
This is a OEM John Deere Part.