UV Light Meter for Measuring UVA Light Radiation From Natural and Artificial Sources. The Extech UV510 UV light meter measures UVA light radiation from natural and artificial light sources. It offers a backlit dual display, cosine corrected sensor, two selectable ranges, zero function, min/max recording, display hold, and auto power off. Compact size with handy wrist strap gives you convenience in taking quick UV reading wherever you go.