A pair of Giant MPH hydraulic disc brakes.
160mm rotors, 6 bolt, IS mount for front and rear calipers.
This came supplied on a Giant bike, and have been used a bit, but are still in good condition. I think they are still on the original brake pads, with plenty of wear left in them.
I'm not sure if I have the manual for these, but it seems to be available to download here (it may be a sightly different model, but it looks very similar): http://www.wrower.pl/instrukcje/Giant/2001-MPH-3_owners_manual.pdf
A warning: these can be prone to jamming on. You may be able to fix this by replacing the fluid / bleeding the brakes. Or it may be that the adjuster wheel is jammed (they are a closed system). There's simple instructions to fix that in this thread on the CTC forum
Hence the rather cheap price: £30 posted for the lot