The 15DIFF-VIS Flashed Opal Optical Disk Diffusers is significantly less expensive than integrating spheres and is easily mounted in a simple optic holder. Diffusers scatter incident light, thereby reducing the sensitivity of a detection system to slight positional or angle changes in an incoming beam. They can also be used to improve the uniformity of a light source. For many measurements, particularly of very low signals, optical disk diffusers are more practical and economical than other diffusing options. This 1/2 inch (38.1 mm) diffuser has a thin diffusing glass coating bonded to a clear glass substrate. It is close to ideal in performance, which creates much loss for collimated beams as they are now scattered into 4π steradians. Our diffusers' spectral transmittance range is 400 to 2,000 nm, but since short wavelengths scatter more, these are better diffusers for the visible than for IR radiation.