Magnetic ring systems for attachment to a shaft and methods of making and using are provided. Protrusions in two substrates are arranged alternately and the bent portions of the saw-shaped protrusions are placed on the line transverse passing through the center of a pixel. The decoder is split into a first stage and a second stage. In one implementation, encrypted electronic profiles are stored on behalf of users by a profiling system, allowing user information within the electronic profiles to be accessed only by decryption of a portion of the electronic profile by the profiling system using distributed decryption codes. The valve includes an expandable support frame and a valve leaflet, and includes at least one opening that permits a controlled amount of retrograde flow through the valve when the valve is in a closed configuration. This enables a transmissive portion to offer a display with high contrast that does not suffer from afterimage or the like by shielding light from the domain lying between the adjacent pixels, and the reflective portion to offer a brighter display by increasing the aperture ratio thereof by making the black matrix width as small as possible or forming no black matrix.