SpyGlass lens and Viewport allow inspectors to pinpoint hotspots in electrical cabinets while circuits are energized and under load. Require no downtime, encouraging frequent inspections. Use in high- and low-voltage applications. Install in 20 mins. in horizontal or vertical position. Viewport uses only -in. aperture, eliminating need for infrared transparent window or metal screen barrier. Resists moisture, dirt, and UV. rays. Never needs cleaning. Fish-eye SpyGlass offers wide field of view: 53 horizontal by 40 vertical or 66 diagonal. Measures temperature with accuracy of 3 C. Boasts focus range of 4 to 45 ins. for use with different cabinet depths.