The first time burglars broke into the offices of Lorell Press Inc., they made off with two Apple II computers worth $1,500 each. The second time, they only damaged about $300 worth of protective equipment. The computers were left intact.

Lorell, a publishing and commercial printing company in Avon, Mass., made life tougher for computer thieves by installing two security devices on its electronic hardware. The devices -- steel braces that can be bolted to any surface -- are manufactured by Segull Enterprises come in models specially designed for different brands of computers. Lorell's model, the $155 Pro-Tech II, fits the Apple II or IIe.

"Thank God we bought our Pro-Techs as soon as we did," says Lorell office manager Dorothy O'Brien. "Shortly after we installed them last summer, we were broken into again. The braces slowed the burglars down so much that they finally tripped the alarm and were scared off. We had to replace the braces, of course, but that's a minor expense compared to buying new computers."