Astro Optics Pvt. Ltd. an ISO 9001 : 2000 certified company manufactures various types of optical components and lenses are one of them. There are various kinds of lenses. Meniscus Lenses are simple lenses or singlets. A Meniscus lens has one concave and convex surface. Salient features of Meniscus Lens are :

It can either have a positive or a negative focal length depending on the radii of the two surfaces.

This lens can be used in combination with other lenses to increase or decrease the focal length of the system.