Plano-concave lens, Fused silica, Ø 12.7 mm, f = -20 mm, mounted, RAGV

Plano-concave singlet in Fused silica, Ø 12.7 mm, focal length -20 mm, in a mount. RAGV coating. Negative focal length: diverges the beam, for beam expanders and to shorten system length.