For demonstration of interference, diffraction and holography. Laser source and switch mode power supply are housed in a thick aluminium box with a hole through which laser beam comes out. The laser unit is mounted on a precision 1 meter double rod SS optical bench. Intensity of laser beam is 2mW and it is red in color. Input power is 220V AC. Minimum operating life is 15,000 hrs. and shelf life is 10 year. The unit is supplied with single slit and diffraction gratingAlthough this is a very safe equipment to handle still a few precautions will ensure proper safety and long life viz. Operate the laser at least once in a fortnight