A retiring heavy line mechanic asked me if I wanted to buy some of his stuff. Besides some misc boxes full of early 50's Snap-On, Proto, Firestone, John Bean, and other misc items, so far this one Plomb socket turned out to be my favorite rare find. Plomb Los Angeles 1930 - 1931 DDX30 3/4" Drive 1 7/8" socket. Plomb 1930 catalog retailed this for $2.30 and it weighs around 2.5 pounds.
He still has his original rolling toolbox with tools stuck in storage at the dealership so I am hoping when he retrieves it that it has more of these old Plomb sockets.