The EQC Master series HTLS features a 1-1/2" x 3.8" viewing area. Sensitivity adjustment allows users to fine tune the unit depending on ambient light or arc intensity. The variable shade HTLS provides infinitely variable shade selection between 8.5 and 12.5 for adaptability to many welding applications, and allows for hood-down set-up in low ambient light applications. Uses 2 AAA alkaline batteries, with a solar battery life extender for use up to 1200 hours.