This is the G063345331 model from Qioptiq Photonics, a 22.4 mm diameter UVFS mounted double-concave lens with an effective focal length (EFL) of -30mm. The lens is made of UVFS material with the Mal-1965 identification.
The lens features a symmetric concave-concave geometry, with a center thickness of 1.5mm. The radii of curvature for the first and second surfaces are -30.287mm and 30.287mm respectively. The lens does not have an inner or outer radius.
The lens is designed to operate at a wavelength of 355nm and comes with a front and back coating of Qio AL RALVIS AOI 45. The lens shape is spherical, which is ideal for a wide range of optical applications.
The lens is currently in stock and can be purchased directly from the Qioptiq Photonics website. For more information, please refer to the provided weblink.