Feature: 1. AUTO ON AND OFF: The lens has automatic opening and closing function, the operation is simple and safe, and it can be used with different styles of welding masks. 2. ADJUSTABLE SENSITIVITY: The knob of the lens can adjust the sensitivity, which is convenient and quick, and the signal light will alarm when the battery is low. 3. WIDE VIEW: The lens is clear and the field of horizon is wide, which can quickly and reliably filter the welding arc and improve work efficiency. 4. PROFESSIONAL PROTECTION: The high sensitivity arc sensor and probe head on the lens provide you with professional and accurate protection and effectively prevent the occurrence of occupational diseases. 5. PP MATERIAL: PP material is non toxic, odorless and tasteless, and is one of the lightest varieties of all plastics, which can reduce the workload. Specification: Item Type: Auto Darkening Welding Lens Material: PP Frame Size: Approx. 110 x 90 x 9mm / 4.3 x 3.5 x 0.4in Window Size: Approx. 100 x 50mm / 3.9 x 2in Bright State Color Grade: DIN4 Dark Color Grade: DIN9-13 Dark State Color Number Adjustment Method: External control, stepless adjustment Dimming Response Time: 1/10000 Seconds Induction Sensitivity Control Adjustment: Infinitely adjustable Recovery Time: 0.1 Second-0.8 Second Power Supply: Battery,Solar Battery Specification: 2 x 3V CR2032(excluded) Working Temperature: -20℃-65℃ Number of Arc Sensors: 2 Infrared or UV Protection Class: DIN16 Self Check Function: Yes Low Voltage Alarm Function: Yes Grinding Function: Yes Cutting Function: None. Package List: 1 x Auto Darkening Welding Lens Note: Keep it properly when idle to avoid damaging the mirror