Vaco / Klein Split Blade Screw Holding Screwdrivers Review

In this video we look at some vintage Vaco 'split blade' screwholding screwdrivers.
This design dates back to 1948 (or maybe even earlier) but is still being produced today by Klein & QuickWedge.

Here are the patent numbers if you wish to look at them:
1948 GW Barlow: 2,445,383
1965 CM Osborn: 3,224,479
1978 E Benitz 4,078,593