Auto Darkening Welding Helmet; Many color for your choose; Different designs for your reference Auto Darkening Welding HelmetTechnical Parameter: DX-300F DX-350D DX-400SOptical Class ... External,Variable Power On/Off:Fully Automatic Sensitivity Control:Unadjustable,Auto Low — High, by infinitely dial knob Low-High, by ... Light to Dark Dark to Light:0.25-0.45S Auto 0.1-1.0S by infinitely dial knob 0.25 ...