1. Mainly consist of crust, gas or solid tube arrester, thermal resistance PTC, reed and base pin; 2. Cladding: phosphorus bronze and silver plating(20-40uinch); 3. The performance of anti-burn ABS(UL94V-0), Combustibility achieved GB/T 5169.7-1985 standard; 4. Insulated resistance: under satndard atmospheric pressure, the insulated resistance is not lower than 1, 000M ohm; 5. Over voltage and over currency protection: meeting the industry standard; 6. The performance of fail safe: when discharge achieve 2.5Ar. m. s. The a line or b line should be 5-15s internal earthing in the discarge loop;