Each unit is factory calibrated and comes with calibration references to maintain accuracy and a one year warranty. Straight forward, economical and accurate. The standard unit comes with a fixed 2mm aperture. Two options packages provide interchangeable apertures from 0.5 to 3.0mm and the ability to remove the reading head to accommodate large subjects. Attractive and nicely made.
Various options are available including a polarization filter for measuring wet film.
TD - Optimized for transmission measurements with a fixed 0.5 aperture. TD 2 - For transmission measurements of diazo films.