(1) GL Spark Plugs feature a copper core for its superior electricity conductivity. (2) The amount of Aluminium oxide reaches 95%, it has better insulation, heat dissipation, resistance against heat shock and mechanical failure. (3) The Ground electrode is made of nickel-manganese, ablation resistance. (4) The insulator glass is made from copper power, under the temperature more than 800 centi-degrees, the copper power crystallizes, the sealing glass can stand high temperatures. (5) Terminal: is made of ML10 steel, after assembly and testing the pull experiment, it can reach and even over the national standard. (6) The central electrode is made of nickel chrome or nickel and copper. It has good conductivity and prevents oxidation and corrosion. (7) Multi-ribs designed on the insulator. (8) Nickel-plated shell prevents oxidation and corrosion,electrical heat crimping process ensures reliable sealing. Testing (1) We test the insulator one by one under 25~35KV to ensure the insulation. (2)The intensity of the Housing and Shell. (3)spark over test. (4)the bend of the ground electrode. (5)cosmetic inspect. (6)other tests according to the National Standards. Please mail us, for your requirement.