Seiko Prospex Solar Divers Black Dial SNE556P1 SNE556P 200M Mens WatchSeiko Prospex Solar Diver's Black Dial SNE556P1 SNE556P 200M Men's WatchThe Tuna USP are manyfold; the high grade ABS shroud is just one of them. It protects the case and the bezel, adding strength to the steel and imparting it the shape of a tuna can. Hence the name. This one is a slightly scaled down version of the actual Tuna with a few modifications among which, the almost lug less case is the first one to catch your eyes.