When procuring mobile surveillance units, prioritize high-definition imaging (at least 4MP/2K resolution) and H.265+ video compression to save bandwidth and storage. For off-grid reliability, ensure the system features high-efficiency monocrystalline solar panels and LiFePO4 (Lithium Iron Phosphate) batteries, which offer a longer lifecycle than lead-acid alternatives. Additionally, verify the PTZ (Pan-Tilt-Zoom) capabilities, specifically looking for at least 20x optical zoom for long-range monitoring.