Plano-concave lens, N-BK7, Ø 25.4 mm, f = -500 mm, mounted, ARHS-YAG

Plano-concave singlet in N-BK7, Ø 25.4 mm, focal length -500 mm, in a mount. ARHS-YAG V-coat coating. Negative focal length: diverges the beam, for beam expanders and to shorten system length.