Wikipedia
The CrustaStun is a device designed to administer a lethal electric shock to shellfish (such as lobsters, crabs, and crayfish) before cooking. This avoids boiling a live shellfish which may be able to experience pain in a way similar to vertebrates. The CrustaStun comprises a stainless-steel box approximately the size of a domestic microwave oven containing a tray with a wet sponge and an electrode. The shellfish is placed in the box and when the lid is closed, the wet sponge conducts the current which electrocutes the animal. The device works by applying a 110 volt, 2–5 amp electrical charge to the animal. It is reported the CrustaStun renders the shellfish unconscious in 0.3 seconds and kills the animal in 5 to 10 seconds, compared to 3 minutes to kill a lobster by boiling or 4.5 minutes for a crab.
The inventor of the device, Simon Buckhaven, worked for two years with scientists from the University of Bristol to develop the device which is manufactured by a company in England, at an estimated cost of £2,500 (in 2009).
There are claims that shellfish killed with the CrustaStun taste better than those killed by boiling. Waitrose, Tesco and other major supermarkets in the United Kingdom have insisted that all shellfish products supplied to them are killed using this method.