We will show that with the proper integration of process, adsorbent kinetics, and hardware, even four bed systems can be cost effective across a fairly wide range of production rates. We have developed such a four bed PVSA process which can achieve up to 70% recovery at 93% purity. There is no idle time for either the compressor or vacuum and no product tank is required. Process simulation was used to develop the cycle, which was then confirmed by experimental data. Important hardware and adsorbent issues to enable development of commercial systems based on the process will be discussed.