Are Cain's clocks not surface mounted..? I mean, with a flat rear. The mounting plate looks flat enough..
Not quite. The clock itself mounts to a backing plate via 4 tiny little capscrews, and the backing plate has an M6 (from memory) CSK setscrew to allow it to be bolted to wherever it's mounted. I suspect you could dispense with it and rely on double-sided tape instead, but I used the bolt on my dash.
