Model: Coronet B
Cell type: Selenium
Measure type: reflecting/averaging
Walz began as the export arm of Okada Optical in Japan, but eventually became simply Walz (at least in the US). They made a few cameras, but I mostly know them for their accessories: namely filters and the odd light meter or two. It was Walz, for instance, which ended up with the Norwood Super Director.
This is a Coronet B—I haven't yet seen an A model. Nothing special about it; it's like many other meters that flowed out of Japan at the time, in particular the Sekonic L-6 and Showa-Koden's Unittic IX (not in my collection). My guess is that this is a tweaked L-6.
There are two Coronet B's. This silver one and a later black-cased one, which had a slightly different calculator dial.
Acquired this the old-fashioned way—when I purchased a movie camera "outfit" from a thrift store..