Dear All, Appreciate if you can guide me on understanding the ultimate pressure of vacuum pump. I have two models for review. One has ultimate pressure of 1 x 10^-4Torr the other has 2 x 10^-3Torr. From this can it be said that the vacuum capability of the first pump (1 x 10^-4) larger range? is better than the second pump? Both has speed 35CFM. Model 1 Pump WELCH 1375 Model 2 Pump PFEIFFER DUO65 Thanks for your help.