The Speedmaster “Pocket Pal” SM-12 has been designed to meet industry’s needs for a small portable densitometer. With a range of 0 to 4.00D, the “Pocket Pal” provides a quick and effective method to verify that your B&W or x-ray film processor meets all quality control requirements. No separate light source is required, just insert the film, align the area to be read, and press a button.