Biconcave lens, Fused silica, Ø 22.4 mm, f = -20 mm, mounted, ARB2-VIS

Biconcave singlet in Fused silica, Ø 22.4 mm, focal length -20 mm, in a mount. ARB2-VIS broadband AR coating. Negative focal length: diverges the beam, for beam expanders and to shorten system length.