The Spy Bolt is an updated and improved version of the old Soviet KGB "dead drop" hollow bolt used during the Cold War. It features an O-ring seal for weather-proof storage of small valuables, communications, etc.
Simple, ingenious design is essential for the concealable gadgets spy work calls for. The Spy Bolt fits the bill perfectly. This new version utilizes a ¾" diameter bolt providing a larger storage area than the original. It also features reverse threading on the bolt head for additional security.