The Double Concave Lenses are made from BK7 material, which are manufactured with both surfaces concave. These lenses have negative focal lengths. These lenses diverge collimated incident light and form virtual images, which are seen through the lens. They are often used to expand light or increase focal lengths in existing systems. They are used in laser beam expanders, optical character readers, viewers, and projection systems. We will provide precision grade Double Concave Lenses with tighter manufacturing tolerances.