"When a tank of fuel was worth $90, a padlock was enough. Now that a tank may hold much more in fuel, it's worth the extra effort to protect it," says Dick Bittney of Webster City, Iowa, inventor of a new "lock box" for fuel storage tanks.

Bittney's lock consists of a heavy gauge steel box that locks over the tank flow valve and fittings. One end of the box is removed with a key. To turn on the gas, you pull off that cover and reach in with a small tool that hangs by the side of the lockbox, and turn the valve.

"Any thief can pop a padlock off in minutes, but this lock is almost impossible to break into without special equipment. Not only is it constructed from heavy steel with a cover that cannot be pried open, but the entire box spins so that if a thief did try to break into it, he would find it difficult to work on," explains Bittney.

Besides the flow valve lock, which can be mounted ahead or behind the gas filter, Bittney has also invented a similar lockbox for filler caps on fuel tanks. Made from the same heavy steel, it installs over the filler cap and also spins to frustrate thieves.  No special tools are needed to install them.