Knife Lock, Locking terminal for 1/2 inch ribbed channel balance.
Used primarily on the vinyl tilt in jambliners (D70 Balances) for wood windows

Available in White or Black, Both are made the same but the black is used to denote the Heavy Duty Balances

Black terminal is used on heavy duty balances: HD, TG, and XHD Balance.
White terminal is used on standard duty balance.

Priced and sold each.