PR-810L is unlike any of our previous photomultiplier tube (PMT) based photometers - it's battery powered! The Lithium-ion battery provides more than 12 hours of continuous operation providing the ultimate in portability. It also features a full color touch screen display, and 75 mm objective focusable from 14" (355 mm) to infinity.Other hardware features include AutoSync® for automatically synchronizing to the source refresh rate insuring the utmost accuracy, an External Trigger Port allowing remote measurement activation from either a push button or peripheral device, a Secure Digital (SD) port for measurement storage.Using the largest of the 4 fully automated apertures, the PR-810L can measure 1E-6 (0.000001) footlamberts. A fully automated Neutral Density (ND) filter turret provides 3 decades of filtration (10X, 100X and 1000X attenuation) resulting in a 900,000,000:1 dynamic range in any aperture - wide enough for any contrast measurement task. The total instrument dynamic range is 518 Billion:1.the PR-810L is supplied with a USB interface and driver. The driver establishes a virtual COM port making control of the PR-810L as easy as communicating over RS232. If a traditional RS232 interface is a must, it can be supplied to complement the USB I/F. Want to go wireless? A Class 1 Bluetooth interface can be added for control of the PR-810L up to 100 meters away.