LP345 Windows are made from made from precision polished BK7 optical crown glass, resulting in no image distortion and excellent transmission in the visible and near-infrared spectrums. They are environmentally stable, stain-resistant and virtually free of bubbles and inclusions. MidOpt LP345 Windows are precision double-side, “flip” precision ground and polished and are coated on both sides. These durable broadband, multilayer anti-reflection coatings limit glare and other reflection losses while helping to achieve optimal image quality.