An elusive variation in the 1910-12 Sweet Caporal Pins P2 set features Roger Bresnahan with his mouth open.

Though his expression hardly conveys exasperation, the legendary catcher exhibits what might be his reaction if he was alive to see how little his pin sells for. A PSA EX-MT 6 copy garnered just $109.84 on eBay in November 2007.

The inexpensiveness of these pins appeals to hobbyists.

"What really attracted me to the pins was the affordability, and that I could collect something in a vintage state that was a little more affordable than trying to collect a monster set like the T205 set," said Tom Lane, who owns the registry's No. 2 All-Time Finest set.

David Burmon, proud proprietor of the registry's No. 5 All-Time Finest set, collects for similar reasons.

"I wanted something that was pre-war. I wanted something that was attainable and wasn't going to cost me a fortune," he said. "The pins are much more affordable than the cards."

These pins have been closely linked to the T205 Gold Border set. The two offerings share many of the same pictures and all but nine players in the Sweet Caporal issue are also featured in the T205 set.

Inserted in cigarette packs from 1910 to 1912, these sepia-colored pins measure 7/8" in diameter. A picture, player name and team are showcased on the fronts, while the backs flaunt Sweet Caporal advertising and production information.

David Duke, owner of the registry's No. 6 Current Finest set, has seen pins produced in North Carolina and New York. Manufacturing these pins in multiple locations may have contributed to the design variances. For example, some pins boast black paper inserts on their backs, while a smaller quantity showcase red inserts.

Small and large letter versions also exist of some pins. The larger letter variations feature the player's name and team in a bigger font.

"The large letters are really, really different from the small letters," explained Lane. "Generally, the larger letter examples are in better condition than the smaller letter ones."

But the larger letter versions also tend to be more difficult to find.

"I'm assuming that the larger letter versions came out a little later. They were a lot less populous," said Lane.

For a complete set (204 pins), hobbyists are generally expected to amass the small (153 pins) and large letter versions (51 pins).

Three versions have surfaced of Bresnahan. On top of the mouth open pose, small and large letter versions with his mouth closed are also in circulation. The small letter variation is the most common.

Three different Bobby Wallace pins have also surfaced. Large and small letter versions showcase him with a cap, while a rarer variation depicts him without a cap. Of the 18 cap-less Wallaces, there have been two PSA NM-MT 8s. One sold for $167.20 on eBay in February 2007.

Aside from its variations and affordability, this set also boasts tremendous player selection.

"It's got about 45 to 48 pins of Hall of Famers," said Lane.

Four of baseball's most celebrated legends -- Ty Cobb, Cy Young, Walter Johnson and Christy Mathewson - are part of this offering. Small and large letter versions exist of all four. The Georgia Peach's pins have garnered the most at auction. A PSA MT 9, small letter Cobb fetched $2,325.99 on eBay in May 2007.

Lane says the most elusive Cooperstowner to uncover in top condition is Rube Marquard.

"He's not the rarest pin out there, but he's definitely the rarest Hall of Famer out there. You don't see that pin very often," he said.

Only 14 Marquards have been evaluated, and just one has graded as high as PSA NM-MT 8. A PSA NM 7 sold for $202.50 on eBay in May 2008.

Less than 10 copies of Danny Hoffman, George Stone, Sam Leever and Topsy Hartsel have been submitted for grading. These low-population pins generally sell for premiums. A PSA NM-MT 8 Leever, for example, commanded $501 on eBay in February 2007.

In general, these pins can be found in better condition than their tobacco card counterparts.

"To be honest of all the pins that I've come across, I barely ever see any that are dinged. But cards are handled nonchalantly left and right, probably every day by a kid," explained Duke.

But he points out that there are still some condition issues with these pins.

"The tobacco stains are rampant in this collection -- not only on the front, but on the back also," he said.

Rust can also present a problem.

"The back rim of the pin rusts," said Lane.

Poor centering can be an issue as well.

"I've seen a lot of them so off-center that the team name is off of the pin," said Lane.

The most common problem, however, is damage to the paper inserts on the backs.

"That gets frustrating because you can find a beautiful pin and the insert is off-center or half gone," said Burmon.

These pins are generally more difficult to track down than tobacco cards from the same era. So far, this relative scarcity has not translated in added value, though Duke points out that the pins are "becoming more and more popular."

But even with this spike in popularity, Sweet Caporal pins remain undervalued.

"I think this set is significantly underrated. It's a 100-year-old set that includes some of the greatest players ever to play the game," said Burmon.