The Seal-Tite wads were invented during the later 1920s. See all those patent numbers on vintage Western Cartridge Co. shotgun shell boxes. The ones that seem to pertain to the Seal-Tite wads are 1,485,337 - 1,576,759 - 1,577,426 - 1,659,649.
Seal-Tite Wad.JPG
In the 1939 time frame, along with the introduction of the Super-Seal Crimp on their trap and skeet loads they added a seal around the base wad --
Xpert Skeet & Trap Loads with Seal-Tite base wad and Super-Seal Crimp.jpg
After WW-II they went to the Super-Seal Cup Wads --
Xpert with Super-Seal Cup Wads.jpeg
Super-X 12-gauge, 2 3-4 inch SX12H2 Magnum 03.jpg
WW used the Super-Seal Cup Wads well into the plastic shell era.
UPLAND 1980 names combined.jpg