When evaluating light towers, prioritize the mast height and extension mechanism (manual, hydraulic, or pneumatic) to ensure it meets your site requirements. Key metrics include luminous flux (measured in Lumens), where high-efficiency LED lamps are preferred over metal halide for lower power consumption and longer lifespans. Additionally, verify the IP (Ingress Protection) rating, ideally IP65 or higher, to ensure the unit can withstand heavy rain and dust in outdoor construction or emergency environments.