... with or without metal domes 5. Water-resistant, dust-proof, gas-proof and scratch-resistant 6. Long life cycle. Electronic ... installation and connection convenience. 4. Tightness is good, moisture-proof, dust-proof, waterproof, anti-oil, anti-corrosion and erosion of harmful ... gases proof, acid and alkali proof, quakeproof. 5. Low cost, high lifespan, ...