Lincoln Electric’s KP3775-1 2x4 C Series auto-darkening welding lens is a compact ADF cartridge built around 4C® Lens Technology for a clearer, more natural view of the arc, puddle, and base material. It carries an optical clarity rating of 1/1/1/2, runs at Shade 3 in the inactive state, and provides a variable Shade 8–13 when welding. Power is supplied by a solar cell with two replaceable CR1025 batteries, with adjustable sensitivity and a fast 1/10,000 sec switching speed. This cartridge uses 2 arc sensors, is rated down to >5 amps TIG, and fits a 4.25 x 2.00 x 0.32 in. (108 x 50.1 x 8 mm) cartridge size with a 3.63 x 1.38 in. (92 x 35 mm) viewing area. Operating temperature range is 14°F to 131°F (-10°C to +55°C), and the warranty is 2 years.