Rolex engraves or assigns a 4-6 digit model number to every watch type it produces. This number can be found engraved between the lugs on the side of the case above 12 o’clock. The model number can indicate the model type, bezel, and material of your watch. For example, the reference number 16234 can be broken out into three section, which is 162 | 3 | 4. The first, 162, indicates that this watch is a Datejust. The second, 3, indicates that the bezel is fluted. The third, 4, indicates that the watch material is Stainless w/ 18k White Gold.