Howard Ladig manufactured his 
"Jet" Plugs from approx. 1952 - 1957 in Wrentham, Mass.; at this time the only models that I am aware of him offering the public are swimmers and poppers.

   If you would like to learn more about Howard Ladig; be sure to read 
Tom Clayton's in-depth article published in the 
Jan.- Feb. 2008 issue of Hunting & Fishing Collectibles Magazine.