This format is used to create images without compression on Nikon Coolpix cameras. The created RAW files contain electronic data from the camera sensor. It is able to save more data compared with compressed photos. With NRW files you can set the exposure, white balance and other settings while preserving all the details in the image.
This format is a vector images file in the Sketch Drawing program, which serves to edit and create interface designs, applications and software shells. SK-files contain objects and layers which can be edited independently of each other.