its a 650b frame, there is a 700c version also but this is specifically designed for 650b so geometry is slightly different in that the chainstays are 20mm shorter (405mm) less bb drop & the sizing is slightly different regarding reach. tyres are 47c on 23mm internal rims. a 2.0 tyre will fit - just.
@conv3rt: probably around £1300 lot of the parts picked up used for cheap. a few alterations since this photo was taken will upload something more recent soon..