This is a sprocket for Velvet Drive 72 series transmissions, part number 1308-144-010. See the 72C series for more.
Item V21 (sprocket, 36 teeth (used in 1.21:1 ratio)) on the Velvet Drive 1004 and 1005 V-drive parts diagram (Fig 12 V-drive gearbox). One per transmission.
Item V30 (sprocket, 36 teeth (used in 2.50:1 ratio)) on the Velvet Drive 1004 and 1005 V-drive parts diagram (Fig 12 V-drive gearbox). One per transmission.
See item V21 on the parts diagram · See item V30 on the parts diagram