It’s a good idea to keep dangerous power tools and appliances out of the hands of people who don’t know how to use them correctly, but who wants to keep everything in a tool crib like your shop teacher did? The Stopower cap offers a better solution, firmly locking onto any 115V American-style two- or three- pronged plug, requiring removal (with a key) before you can plug the attached tool into an outlet.
Other lockout solutions close around the plug and require a separate padlock. These locks come with their own individual keys, you can order larger numbers keyed alike. They cost between $10 and $16 dollars each, depending on the vendor. Of course, the fact that the small ones don’t require an individual padlock for each unit offsets some of the cost.
But who can put a price on preventing little Johnny from taking your recip saw out for a test drive?
Note: The Stopower is a little scarce on Google Products. Try a Google search for “Stopower lock” for more results.