Features variable shade 9-12, sensitivity and delay adjustments. Four independent sensors with low voltage indicator lamp. Technology allows unit to detect welds less than 5 amps. Requires 2 AAA batteries (included). Meets the ANSI Z87.1 standard. W40 series auto-darkening filters: enables welders to adapt to the vast working environments with the ability to control the shade of the lens and adjustments for sensitivity from ambient lighting sources. Measures 5" length by 4" width.