The lens casing is 212 x 190 x 52 mm according to my own measurement. To this comes the front plate with the handle and it is 219 x 55 mm and extends 39 mm outwards ( from the casing to the outer end of the handle ). All condensers for the Durst 138 have the same outer size. Only the size of the lens differs. They go from the smallest one ( 85 ) with a tiny litle lens on the bottom plate to the big piece of glass that almost fills out the entire casing of the 240 . I measured the bottom glass surface of the 240 and it is 194 x 158 mm . I hope this is of some help. Good luck.