I bought a Durst Laborator 1200 recently. With it came, among other things, these masks. They don't fit the Laborator 1200 though. Can they be suited for the Laborator 138 of 139 ? I don't know anyone who owns one. The dimensions are 13 x 18 cm (5x7 inch) on the outside. They are quite heavy and the bottom mask has pins on it.