Jackson 0744-0660 HSL-100 EQC Master Variable HTLS Welder's Helmet. HTLS (High Transmission Light State). Allows the Serious Welder to Work in Almost Any Welding Application. Auto Darkening Lens Features: EQC Technology Powered; 1-3/4� x 3-3/4� Viewing Area; On/Off Switch w/Auto-Off; Sensitivity Adjustment; 4 Independent Redundant Sensors; Uses 2 AAA Batteries; Solar Battery Life Extender; Low Voltage Indicator Lamp; Variable Shades 9 - 12; Delay Adjustment; Fits HSL-100 Series Hood (4-1/2" x 5-1/4"); Intellisense (Allows for 5 Amp & Below); Mounting - Vertical.