Strad-O-Lin
The Strad-O-Lin company of Chicago, active in the 1940s, farmed out
some of its production to various small-shop luthiers, resulting in a wide
variation in quality among its acoustic mandolins. Some are merely
adequate, and some are quite nice. The company also produced a few
electrics. The one on the left is definitely a Strad-O-Lin, but I'm not
sure about the one on the right. (I have played one, and it wasn't that
exciting.) As for the one below, it appears to be an oval-hole acoustic
that someone tricked out with a pair of pickups.