Date unknown, but $5.95 got you a pair of these bad boys including postage east of the Mississippi.
Also, no zip on the address. 5 digit zip was introduced nationwide in the US by 1963. So this may be 50's or at most very early 60's.
I'm old enough to remember these, or at least something like them. Even if they were "Made to last for years.", no one played with them more than once. That was all it took to discover how stupid they were.