The 77250-FH is a fully assembled, pre-aligned, Hand Operated Monochromator. The monochromator is based on an Ebert-Fastie design, placing the grating out of the path of the entrance and exit slits to eliminate re-entrant spectra. The hand operated design allows for output wavelength adjustment as accurate as 1 nm. A three digit counter display displays the output wavelength with resolution as great as 0.1 nm. Fixed Slit widths ranging from 50 µm to 6.32 mm in width (sold separately) are interchangeable, depending on the output resolution desired. These slit assemblies are ideal for general laboratory or academic use, in which a high accuracy and repeatability (especially at high resolution) are desirable. Fixed slit assemblies also provide a cheaper solution than the micrometer adjustable slit version of this monochromator, the 77250-MC, when only a few slit widths are required. Gratings are interchangeable, depending on the needs of the application, and cover a wavelength range from 200 nm to 23 µm. The 77387 mounting kit (sold separately) allows the monochromator to be mounted in a setup with an easily adjustable optical axis height to match that of a source and/or detector.