The dial design has just one objective; maximum legibility, even deep in the ocean where sunlight does not penetrate. The hour markers are large, so as to allow the maximum surface area and depth for Seiko's Lumibrite coating. The hands, too, are wide and easy to read. The crown has screw-down protection to prevent it from being pulled out by any accidental operation. The watch is designed and manufactured to withstand up to 200m going under the water, and is suitable for wearing while scuba diving.