Published: Oct 22, 2013 3:04 PM EDT

ST. PETERSBURG, Fla. (AP) - A Florida museum is showcasing what Guinness World Records has certified as the world's largest collection of autographed baseballs.
    
The exhibit opened Tuesday at the St. Petersburg Museum of History.
    
It's called "Schrader's Little Cooperstown" after Dennis Schrader, the Florida man who collected all 4,600 balls.
    
Schrader attended the exhibit's opening. He began collecting signed baseballs in 1956 when he was 9 years old and New York Yankees star Mickey Mantle inked one for him at spring training.
    
Previously, Schrader's baseballs were displayed in a 12-by-14-foot room in his home that had walls a foot thick, a bank vault door, motion sensors and video-camera surveillance. He estimates the collection is worth $2 million to $3 million.
    
Schrader says he will continue collecting signed balls and will add them to the museum's collection.

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