"Turns out that four of these were actually commissioned/used by the Colorado Rockies for Opening Day in the year 2000. They were made by the Boulder Blimp company and have extremely durable construction with 2.3 Amp Blower Fans, with velcro across the top so they can be "filled" with Helium Balloons and then 'ripped' open to release 'em.
"One has a slight tear that safety pins will handle ... so it was $10. The other was $35 ... so $45 for the biggest balls around -- not too shabby of a deal, 'eh?"