Zoom lens
The Compact Zoom lens was designed for use with wavelength-division-multiplexing systems but is also useful for optical laboratory applications, including spot-size adjustment, alignment, and beam collimation. The lens assembly has an arbitrary focal length ranging from 18 to 90 mm, speed of f/4.5 to f/20, and works at 633- or at 780- to 830-nm wavelengths.
APA Optics, Blaine, MN