COTS is an acronym used by industry and the military that stands for Commercial Off The Shelf. This is as opposed to purpose-built products. Many people see this as a method for the U.S. military to save significant amounts of money; using widely available commercial products instead of complex, overengineered, one-off and expensive military-spec systems.

One excellent example of this I have seen personally is aboard a Los Angeles Class submarine of the U.S. Navy (SSN-751 USS San Juan). In a space in the ship's CIC where a printer was intended to go, there was a bunch of miscellaneous stowage, because the enormous milspec printer that had been there was removed when its cartridges proved unable to handle the varying ambient pressure of a submarine. In the middle of this space was a small Canon Bubblejet BJC printer which the crew had picked up at the base PX for $100. Besides occupying one-sixth the cubic space and costing around $4,500 less, it worked, and only required a bungee cord to hold it in place during maneuvers.