When sourcing ULV (Ultra-Low Volume) foggers, the most critical factor is the droplet size, which should ideally range between 5 to 50 microns to ensure the disinfectant stays airborne long enough to cover all surfaces. You must also verify the motor power (typically 600W to 1200W) and the spray distance, which for professional units should reach 6 to 10 meters. Additionally, check the tank capacity (common sizes are 4L, 5L, or 10L) to ensure it matches the scale of the intended usage scenario without requiring frequent refills.