The P2B model is a 2nd generation version of the AvertX NVR. The primary advantages of the P2B model over the P2A model are smaller size (9.625” vs. 17. 75” depth) and more processing power. The P2B model NVR has a dual processor for improved video performance and the ability to better support 4MP cameras. The P2A model NVR hardware offers limited support for 4MP cameras, and is best suited for 2MP (1080p) cameras. This table shows the specifications of both models (16CH) side by side.