The Elmo 9831, also called QT3515, is an ultra-micro-mount lens for the specialty 1/4-inch CCD pencil-sized cameras, namely the QN42H. The lens has a 7mm screw mount unique at Elmo for these amazingly slim industrial cameras. As a 15.0mm, the lens shows a 13.5 deg. horizontal angle of view. Its f/3.5 maximum aperture allows the lens to capture images in normal lighting conditions.