When sourcing a Lightning Protection Box (also known as an SPD Box), you must prioritize the Maximum Continuous Operating Voltage (Uc) to ensure it matches your local grid stability. Key metrics include the Nominal Discharge Current (In) and Maximum Discharge Current (Imax); for industrial applications, an Imax of 40kA to 100kA is standard. Additionally, verify the Voltage Protection Level (Up), which must be lower than the impulse withstand voltage of the equipment you are protecting. Ensure the internal components use High-Energy Metal Oxide Varistors (MOV) or Gas Discharge Tubes (GDT) for rapid response times, typically less than 25 nanoseconds.