Focusing Prism Spectroscope - If you have been having problems with a fixed focus spectroscope this may be the solution you are looking for. This spectroscope has been used throughout the world for more than 35 years & is recognized and respected by gemmologists & gemmological teaching centers worldwide. It is an ideal inst ent for a small gemmological kit, or is easily carried in a pocket. Perfect for use at antique fairs, for field use or general study purposes. Size:Length:75mm (closed) Diameter:17.5mm Please note:the physical slightly color difference or difference, does not affect the use, please do not mind, thank you! Colour:Black Material:Metal Package Contents: 1 * Spectroscope Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.