The drawbacks of working in an office are plentiful and well-documented. Lots of caffeine is needed to deal with the indignities endured daily by cube dwellers, but that’s pretty hard to achieve when some jerk keeps stealing your coffee mug. Designer Efrat Gommeh is sticking it to the mug thieves with this brilliant design that she calls the Lock Mug.

Each mug comes with a little plug that fits perfectly into a small hole in the lower side of the cup. When you put the mug away in the cabinet, you take the plug with you so that anyone who gets the bright idea to take it will watch their precious java quickly drain away.

The design received an honorable mention in the “Design a Key and What it Opens” competition from Designboom and Beck’s. It’s now available in Germany as a product called My Cup. It might not be as obvious as putting a picture of your face on your mug, but you’ll have fun answering all of those questions about what in the world that red thing is on your key ring.