The N-BK7 rods are designed for use in a variety of laser and imaging systems. Custom rods can have the ends blackened, diffused and optically polished or angled. Specifications: Material : N-BK7 Diameter : 0.5-300mm Dimension Tolerance :+0.0/-0.05mm Surface Quality :80/50 , 60/40 , 40/20 Bevel : Protective bevel as needed Realpoo Optics is a professional manufacturer of optics. Optics includes spherical lens, aspherical lens,diffraction grating, glass rod and flat lens. Spherical lens such as cylindrical lens, ball lens, convex lens etc. Flat lens includes optical window, fresnel lens and mirror.