A Rolex Oyster Perpetual "Pre-Explorer" in stainless steel.  This model Rolex is also known as the "Pre-Explorer" due to the fact that it was the first example of the new, larger, Oyster case to have an Arabic 3-6-9 dial.  This very attractive looking and early Rolex was the second model that can call itself the father of what is regarded as the Explorer.  The 6098, launched in 1950, is regarded as the first iteration. This two piece case was then updated to this three piece case in the early 1950's.  Case back has the reference 6299 struck through, and below it 6298 stamped, with the date code II 56 for the second quarter of 1956 production.