Nylon Vault Key-Hole SignalsNylon vault key-hole signals are color coded by category. Colorfast, won't chip, and reusable with prongs that securely engage lock tumblers for tight key-hole fit. Withdraw and use again as needed. Offset head properly centers signal over key-hole opening. One universal size, 7/8" prong with 1/2" head, designed to fit most popularly used brand locks. U.S. patent no. 4,118,962. White vault key-hole signal means "Box is for Rent". Material(s): Nylon; Color(s): White.