The 70671 General Purpose Integrating Sphere is a 4 inch (102 mm) diameter, Barium Sulfate coated sphere for a 360 to 700nm range with (3) 1 inch ports. It includes standard Oriel 1.5 Inch Series flanges and 1/4-20 tapped holes for rod mounting. If you need to couple this spheres to instruments with male flanges (such as a monochromator), order the 77829 Coupling Ring. It offers high lambertian diffuse coating, accepts a variety of port plugs and detector adapters, and is ideal for universal measurements and mixing two inputs for lambertian sources.