I can see one difference might make it more expensive [tongue] [unsure] The CMT has (I assume) 4 screws holding the digital in the level housing and the clarke has only 2! The little block dots either side of the digital readout is what im referring to!
But I see your point though! Clarke is cheap stuff! Alot of it sold by MachineMart in the UK http://www.machinemart.co.uk/