The Kel-Lite "Firepower" were speedloaders; I don't know if they were the first speedloader on the market, but it was the first type I saw. They were made of rubber; you inserted the rounds into the cylinder and twisted the speedloader, "ripping" the device from the rounds allowing the rounds to fall into the charge holes.
Tex Shoemaker Company(later known as "Tex Shoemaker and Sons" and also as "Tex Shoemaker and Son") is a leather company in San Dimas California (about 20 minutes from my house). They are still in business, and make excellent (IMHO) duty equipment.
I don't know for sure, but I believe current production speedloaders would fit in the "Firepower" holder
(in case you're interested). The holder dates back about 30 years.
Mike