His gizmos go to those with driving ambition.(PEOPLE)(AccuSport Inc)

David Rankin doesn't claim to be a great golfer, but he is helping others improve their games. As president of Winston-Salem-based AccuSport Inc., he has developed a device that records the speed and spin of a freshly whacked golf ball to help golfers choose the right equipment to improve their games. "If you bring in the average golfer off the street, they can be hitting 10 to 20 yards farther with the right club," Rankin, 42, says. "In a game where you struggle to add five yards, that's unheard of."

The 8-pound, briefcase-sized Vector Launch Monitor, which sells for $4,200, was introduced last January at the PGA Merchandise Show in Orlando, Fla. It uses a digital …