The PVX-4140 and PVX-4141 high-voltage pulsers are functionally equivalent, sharing the same electrical specifications and switching performance. The differences are mechanical: the PVX-4141 uses an updated chassis design. Current-production PVX-4140 units also include an updated front-panel PCB and remote signal interface that matches the newer PVX-4150/PVX-4151 design family. For practical purposes, both models are interchangeable in applications. If you are specifying a new purchase, the PVX-4141 represents the current-production chassis revision.