The Meade Series 5000 TeleXtender lineup of Barlow lenses use advanced four-element optical designs which yield superior field flatness & edge sharpness than conventional 3-element apochromatic Barlow lenses. Contrast is enhanced through both the blackening of internal metal surfaces and full multicoatings upon each air-to-glass surface.
Flat field of view
Eyepieces held in barrel by clamping ring rather than setscrew
Machined groove in barrel for safe adhesion with telescope focuser