The weather in Hong Kong is damp and humid, it is easy to make the camera and lens mouldy. The B+W UV-PRO is an easy-to-use option to prevent mould growth effectively. B+W UV-PRO is directly mounted on the camera through the lens mount and is irradiated with UVC ultraviolet light (wavelength less than 300 nm) to prevent moulds such as mirrors, focusing screens, and scorpion. The whole process takes only two minutes (recommended every 30 to 50 days), and it is automatically turned off after completion; plus the lightweight size and support for external battery power, it is convenient to carry. The accessories also support the lens and the mirrorless camera. The former is mounted on the ends of the lens by the adapter, and then each time it is illuminated. It is available in 4 different models for Canon EF, Nikon F, Sony E and Leica M. ring.