Profile: Spectronic Camspec Ltd. specializes in the design and manufacture of UV/visible spectrophotometers. We are an ISO 9001:2000 certified company. Our range of spectrophotometers extends from normal visible instruments through the single beam UV/visible range to double and single beam scanning. They can be operated as stand-alone instruments or PC controlled. In specific our M550 double beam scanning UV/visible spectrophotometer is a double beam instrument with parallel sample and reference beams. It uses an easy to replace tungsten-halogen lamp and a pre-aligned long-life deuterium lamp. Two silicon photodiodes are used for measuring the two beams simultaneously for optimizing measurement accuracy and stability. The reference beam is especially useful for measuring samples where the reference changes with time.