It's wall-to-wall balls for collector Dennis Schrader.
He has more than than 4,600 signed baseballs, starting with the first one he ever got.
Schrader was 9 when Yankees legend Mickey Mantle signed a ball for him during spring training in 1956.
Schrader is now sharing his collection at the St. Petersburg Museum of History in Florida.
He once spent 25,000 on a single baseball, signed by Joe DiMaggio and then-wife Marilyn Monroe.
The massive collection is certified by Guinness as the world's largest.
He also has some balls signed by non-baseball notables, including President Barack Obama.