For those who aren’t up on their tradecraft, a “dead drop” is a place where spies or other clandestine-y folks drop off items for later retrieval by other agents. A “dead drop spike” is a particularly ingenious little container devised for the purpose. Basically, it’s a hollow metal spike, with a threaded watertight closure at the top. You put your top-secret microfilm or whatever inside the spike, take it to your dead drop, and stomp it into the ground with your foot. Then you cover it up with a rock or a piece of trash or whatever. The lid has a pull-loop built into it, so that when your contact comes by later to clear the drop, he or she can grab the spike by the loop and yank it out of the ground again.
When I first learned about dead drop spikes years ago, I had a bit of a nerdgasm and decided I had to have one. I scoured the tubes, but alas, no one was selling them. Imagine my delight when, a couple years later, I discovered that Brian Dereu of Hollow Spy Coins had added a well-machined dead drop spike to his inventory. I ordered one immediately, and could not be more pleased with its quality. That was at least a year ago, and as far as I can tell, Brian and his family are still the only folks selling them online.