The Dive Rite Blackout Mask Training Cover was designed to slip easily over a student's mask and stay in place during lights out or zero-visibility drills. A bungee loop on the right side makes it quick to secure the mask between drills and prevents it from being lost, without having to put it back in a pocket. The blackout mask is a must have for any instructor teaching overhead environments. Face plate cover dimensions are { 6 x 3 in | 15 x 8 cm } and stretches to fit most dive masks.