SINGAPORE (Reuters) - A Singapore firm is selling what it says is the latest motivational tool to get the best from staff -- spy cameras. "Productivity really does go up with this system. You see a very quick return on your investment in any business," said Jeffrey Tan, whose company ABC Asia Pacific markets 'Spy Eyes'. "It is a deterrent for staff who are lazy or who might want to steal from the cash register," he said. Tan told Reuters on Friday he became the Asian distribution agent for the U.S.-made Spy Eyes camera surveillance system after installing it at his own firm to halt sliding sales and cut staff turnover. The system can achieve the latter effect by showing bosses that their staff is indeed working -- or has few customers to sell to -- and thus reduce unjustified management complaints. Tan has already sold at least 10 systems, which can also be fitted at homes for those who want to make sure the thousands of domestic maids employed in Singapore work hard on household chores while their employers are at the office. Costing about Singapore $3,500 (US$2,200) for a single camera starter system, Tan said he was running a special introductory offer for a free second camera for people who wanted to be in more than two places at once. "It's a helpful tool for people who want to stay in control," Tan said.