Teachers helped us design this precise, high-quality instrument, which gives you all the features you want at hundreds of dollars less than competitor's models. The Science Kit Spectrophotometer is a single-beam unit with a wavelength range of 340 nm to 900nm. The unit reduces stray radiant energy to less than 0.5%T. You can use your own test tubes or cuvettes for sample analysis and still receive readability of approximately 0.1%T. Instructions are printed on the front panel for simple start up and operation. There is a scaled spectrum reference on the front panel and a source on/off light switch for luminescent sample readings. 41x21x22cm.