Applications: It measures the total amount of Visual Light Transmission (henceforth referred to as VLT) through a window and any coatings (tint film) on that window. Specifications： Disply: 10mm LCD Accuracy: 0.1 Wavelength: 550 Nanometers Measurement Range: 0 to 100% Light Transmission Interface: RS232C Sample Thickness: Less than 10 mm/0.4inch Sample Size: 50 x 50 mm Minimum Time of Testing: Maximum of 4 Seconds Effects From Stray Light: Not Effected by Stray Light Lamp Life: 10 Years Operating conditions: 0-50℃,<90%RH Power Source: 4 x 1.5v AAA Batteries Weight: 100g (not including batteries) Dimensions: 126 x 65 x 27 mm(5.0 x 2.6 x 1.1 inch) Standard accessories included : Carrying case 1 pc. Operation manual 1 pc. Optional accessory: Cable and software for RS232C