Whirl-E-Gig was one of those terms used instead of yo-yo, back in the days when Duncan owned the trademark on the word "yo-yo". This is a plastic yo-yo with no inner plastic shell, and ribbed on the inner surface. You can see the ribs inside in the main view. With a wooden axle and fixed string, it could easily be converted to a slip string, and likely became quite a player.
A smaller brand from the 50's, Whirl-E-Gigs are very collectible and hard to find.