Bertucci A-4T Nautical 13431 Deep Sea Blue Titanium Nut Brown Derby Leather Watch Rugged U.S. patented DX3 solid titanium case Scratch-resistant hardened mineral glass crystal Durable titanium screw down crown (setting knob) is ergonomically offset at 4 oclock Integrated unbreakable titanium band retention lug bars Titanium screw-down case back