VACO was pretty much the only game in nutdrivers with "insulated" plastic handles into the 60s when Kline and Channellock jumped in. The complete set in plastic guaranteed brittle in winter roll went from 1/4 to 1/2" with 9/16 and 5/8 being additional specials.
Sears also was in the game, primarily through their Industrial Sales operation, with little available in retail stores.
Before VACO plastic handles nutdrivers primarily existed with wood handles in industrial assembly line areas.
In the time before TV advertising lawyers, carpal tunnel, and cheap labor it was cost effective to add a woman to the line turning a nutdriver rather than an expensive air tool.