Calfare Corp., in San Diego, has introduced an antitheft device for shopping carts called the 5th Wheel. The wheel automatically lowers and locks at a 45-degree angle whenever a cart hits a curb or speed bump, and the cart can go only in circles. CEO Ray Calhoun says cart loss is an escalating expense for the country's 33,000 supermarkets, half of which lose at least 50 carts a year. The product reduces replacement and retrieval costs by as much as 80%, he claims. Now selling to 200 stores through equipment distributors, Calfare is pursuing deals with cart manufacturers. While supermarkets, which own 13 million carts, remain Calhoun's primary market, he sees others among retail, drugstore, and hardware chains.

-- Anne Murphy