1950's (?) Speco Max-Mixer Three Channel Mixer

Here is an interesting vintage Max-Mixer by Speco. I'm thinking this may be from the 1950's but I really don't know for sure. It's a passive type mixer with three inputs going into one output. Each input has a volume control. Channel 1 and 3 have 500k pots while channel 2 has a 1000k pot. It's housed in a sleek metal (aluminum maybe?) box with a hardwired cable. It has a screw on type jack with a 1/4" adapter on it. It works as it should with a little static til you work the knobs a bit. This is a bit of a relic but it looks cool and may be great for some low-fi applications.