Brand Rolex Model (Watch) GMT-Master Reference number 16700 Winding Automatic Case material Steel Strap material Steel Production year late 80's early 90's Original documents, NO BOX Case material Steel Diameter 40 mm Water-resistant 10 ATM Bezel material Steel Glass Sapphire crystal Dial Black Numerals on dial No numerals Strap material Steel Strap colour Steel Clasp material Steel Functions Date, GMT