These were sold roughly 30's through 60's. There was a modern version for a while I'll post up later. Some find them useless, some useful and some neat just because they're different (well there is at least ONE who fits that last category).
There were four versions RS4, RS4-B, RS-4-L and RS-4-LB. I have two of them - the bottom two are RS4 the beat to death one I think is dated 39 and the middle one dated 40 but the date stamps are really hard for me to see so I could be wrong although the era is correct. Even though both have the same part number the handle shape differs between them. The top one is an RS-4-L dated 54 (which parenthetically is my favorite date code symbol).
More detail - this thing really saw a lot of use in roughly 80 years but works flawlessly.