Vintage Coil Space Heater

Trying to get a handle on this old guy that I recently pulled out of a garage sale. I've seen some single coiled ceramics, but never a double. Only part of the identification left is a Block "M" at the bottom of the reflector. Wondering if anyone has any idea how old it might be as well as the manufacturer. Any comments at all will be appreciated.
Thanks in advance.\
Mart