Snap-On wrench identification

[30-30remchester]

Have several of these with this kind of handle. I have heard them referred to as "Ibeam" handles. What is there real name and what years were they produced. I have a few from 1957.

 

[Ricky Joe]

They were produced through the 1960s. Thorsen and PowerKraft also had that design, PowrKraft probably made by Thorsen.