This is a multi-purpose optical bench. Used for optical experiments by supporting different optical components to study the laws of refraction, reflection, image formation, etc. Other uses are to experiment with multiple lens assemblies and determine focal lengths. This device could be used with a microscope or telescope. It can also be used to demonstrate the projection of interference, and diffraction and polarization of light. The dual rod optical bench includes: two 1200mm chrome plated rods, a light source (6vdc 3watt), two stands that hold the rods, 100cm measuring device, DCX lens 40mm dia x 100mm focal length, DCX lens 30mm dia x 50mm fl, dcv 75mm dia x -75mm focal length, PCX lens 50mm dia x 300mm fl, and frosted glass 80mm x 120mm. Included are 5 element holders, 4 of which can slide on the rods. Instructions are included to show you how to correctly operate the bench. You will need a 6vdc, 3 watt power supply to power the light source.