Getting into the larger, higher-voltage-rated CP products from the 1930s era, this big 'ol clunky thing is a sort of oddly appealing shape. It's just thick enough to be a little thicker than it needs to be as well as have some of that early engineering crudity to it, but thin enough to not weigh a tonne like the earlier CP stuff does.
This style comes unmarked (like this example), and with an unusually large C.P.Co. marking on the underside of the top shell. The crown is glazed-over, which seems to be unusual for CP multiparts in general. Items from this particular generation (probably mid-to-late 1930s or so?) seem to sometimes have this trait, as it exists on other styles, as well.