Sky-Watcher 2x De-Luxe Barlow Lens

The Barlow lens is used to multiply the focal length Magnifying Power of the objective lens. It is inserted between the diagonal and the eyepiece. The benefits of using a Barlow lens to increase magnification are 1. Improved eye relief. 2. Reduced spherical Aberration in the eyepiece. This Deluxe version of the Sky Watcher Barlow uses two lens elements, as opposed to a single element in the economy version.