Optical dome is a lens with two concentric spheres. They are mainly used for Bathyscaphe, Radiometer, Underwater Robot, Submarine, Camera Image. In an ideal dome, the convex radius equals the sum of the dome thickness and the concave radius, resulting in a naturally strong shape that becomes harder under pressure. This makes the dome ideal for underwater environments and applications such as camera dome ports and dive windows. Sunday Optics is the main manufacturer of optical glass dome lens, and also owns advanced machine and test equipment.