did you know about Rolex Crown system it's made to protect your watch against water Rolex usually doesn't use single lock system all their watches are either twin lock system or triple lock system there are three types of marks on Twin lock system single line two Dot and single dot according to the material of the watch if it's single dot your watch is platinium if it's double dot your watch is gold if it's Dash or single line your watch is two ton on three lock systems you always see three dots on the crown of the watch below the Rolex logo according to the material of the watch these dot sizes can be different if your watch is platinium the center dot is small if your watch is white gold the center dot is big but if your watch is in two ton all the three dots are the same size for example Rolex Daytona