It's sat on my desk puzzling passers-by as they're not too sure if it's work related or not...
They've Included some useful looking fittings, a Stay mount and a couple of cable stop tabs, I think I'll use a full run outer and a V- brake lever.
A quick measure of the Drum and it's 3.5" not 4.5" diameter. So the description seems to be based on rounding up the approximate size of the housing rather than the actual diameter of the brake drum, but I reckon it'll still do the job, there's quite a bit of lining material brought into contact .
A quick fag packet measure up and calc' of areas suggests this thing has approximately twice the pad surface area of a pair pair of disc pads.
Which (assuming the linings have a roughly equal CoF) means that these 3.5" band brakes could be about on par with a 6"cable disc:
Twice the frictional surface area, applied using about half the moment?
I can see how this brake might cook with a bit of heavy use though...