OXFORD – Robert Withee grasps each one with a gentle hand, pointing out different colors, the little nuisances and flourishes in designs that others might never notice, let alone celebrate.

There aren’t too many fans of the lowly spark plug.

In all of Maine, he figures there are five. Including him.

He’s got about 400 spark plugs in his collection. There are, according to the Spark Plug Collectors of America master list, at least 5,000 different documented spark plugs worldwide.

“I’ll never get there, (but) I’m always looking for that next new plug,” said Withee, who turns 70 today.

He’s built traveling cases for some of his plugs, with little holes so they can sit upright. One spark plug is smaller than a thumbnail; it might have gone into a model plane. Some are as much as 100 years old. They’ve got brand names like Bougie Deesse, Bull Dog, Jordan and Splitdorf Electrical. In a couple cases, pristine boxes are worth more than the plugs themselves.

About 18 years ago, Withee started collecting and restoring antique engines; that proved a natural gateway to spark plug collecting when his old engines would need new old plugs.

He and his wife, Debra, find them online, in antique shops and at flea markets. They also go to about 22 engine and car trade shows a year in Maine and New Hampshire.

“We know every antique shop from here to Augusta and down into Kennebunk,” Withee said. Dealers know when he walks in the door what he’s after: that next plug he doesn’t have, or one that he does that’s in good enough shape to trade.

“They’re amazing to look at,” said Debra.

Withee and part of his collection will return to the Oxford County Fair this summer, where he’s the senior museum assistant. The most common questions he gets are where does he find them and what’s a particular plug fit. He’s got the latter explanation down pat: It fit anything that took a spark plug that exact size. Maybe it was a boat, a car, an airplane, a model, a washing machine. (Yes, an internal combustion engine on a washing machine.)

When he brings them out in public, he likes to leave out a box top of random spark plugs free for the taking nearby.

“We’re always looking for new collectors,” Withee said. Maybe a free plug is just the thing to entice a kid’s interest.

There’s room in the club. Spark Plug Collectors of America only boasts 1,300 to 1,500 members worldwide.