I’m not sure what the Mity-Lite was, but was it a lithium battery?
I had a light from the late 60s probably early 70s because it had a moon landing reference. The cool thing was- after over 40 years with the non replaceable battery, it would still come on! No feces! It had a statement on it that said the light may take up to 30 seconds to reach full power. of course after 40 some years, it came on uselessly dim, but it came on!
It burned down along with everything I owned during the California wildfires in August of ‘20!