GRAFTON, Wis. — The Titleist Pro V1 is the best-known ball in golf. When Lashan Wanigatunga started a business in the golf industry, he did not anticipate learning to tell Pro V1 models apart as if they were cars or wines.

“Don’t test me on it,” Wanigatunga said. “But I can usually look at the markings and tell that this is a 2003 or 2004 or 2005.”

An IT professional by trade, Wanigatunga met a neighbor in 2016 who showed off a massive trove of golf balls he’d collected from the woods and water hazards at nearby courses. Wanigatunga had a new business idea and partnered with a friend who works as a course pro. They believed they could buy and resell used golf balls, simplifying the process used by many online retailers at the time. They call their company Two Guys with Balls.

“We are trying to do things a little bit differently so people spend less time messing around on a website with golf balls and more time on the golf course,” Wanigatunga said.

First, they order thousands of golf balls - up to 20,000 at a time - from wholesalers who collect them from courses across the country. It can take weeks to categorize them all by hand. They separate them first by brand, by model and, finally, by quality, using a straightforward scale: eagle, birdie or par. Eagle balls are almost indistinguishable from a new ball, like a new car driven off the lot. Birdie balls may have cosmetic imperfections that would not affect its flight, while par balls are playable, but may have visible scuff marks.

Wanigatunga, a self-described weekend golfer, said unless you are on the PGA Tour, you should be playing used golf balls. But it’s not just about the money.

“Part of it is also reducing waste,” Wanigatunga said. “So many balls get lost in the woods and go into ponds. You are recycling, reusing, and, at the same time, saving a ton of money, as well.”

Two Guys with Balls have sold close to half a million balls in their first five years. Some may have been yours, once upon a time.