The 10RP54-2B Achromatic Quartz-MgF2 Zero-Order Wave Plate consists of two different birefringent crystals: crystalline quartz and magnesium fluoride (MgF2). Enclosed in a 1 inch (25.4 mm) housing this 18 mm aperture zero-order wave plate has λ/4 retardation over a 700 to 1000 nm wavelength range. It has a highly efficient broadband antireflection coating, in an air-spaced design. This construction ensures excellent transmitted wavefront quality, while minimizing beam deviation and surface reflection losses. The assembly is mounted in a black anodized aluminum housing for protection and ease of mounting, with the retarder fast axis marked for alignment reference. Because of the air-space design, our Achromatic Quartz-MgF2 Wave Plates have a higher damage threshold than achromatic polymer film wave plates. Achromatic Quartz-MgF2 Wave Plates are also less expensive than achromatic polymer film wave plates.