Which of the following is NOT a color option for the MK20 mask?

The MK20 mask is designed with specific color options that cater to functionality, visibility, and aesthetics. Among the available choices, black, gray, and yellow are indeed recognized options for the MK20 mask. Each of these colors serves a practical purpose in different underwater environments—black for reducing glare and reflections, gray for a more subdued appearance, and yellow for high visibility, which is crucial in rescue scenarios.

Red, however, is not a standard color option for the MK20 mask. This absence likely ties into the use of color in underwater equipment, where bright colors like yellow are preferred for safety and visibility, while red does not typically serve that purpose in diving equipment. The selection of color options reflects considerations surrounding the user’s needs, safety, and operational effectiveness in various diving conditions.