Dear Dave, We had also problems with Pfeiffer Duo 2.5A during the guaranty time. There are four of them: two for mass spec and two for Kiel device. a) Pump windows broke after 1-2 years (without any external "stress" source) and had to be replaced. b) Pumps lost oil at a interval of c. 6 months and need service. Now the windows seem to be stable but the problem with regularly oil lost is not fixed. Cheers, Ana-Voica ------------------------------------------------------------------------- Ana-Voica Bojar, PhD Institut fuer Geologie und Palaeontologie, Karl-Franzens Universitaet Heinrichstrasse 26, A-8010 Graz, Austria http://www-ang.kfunigraz.ac.at/~bojar