The Small Crown Submariner, particularly the 5508 is known as the charming and elegant Submariner, due to the thin case and small crown. Especially also if it comes on a nice glossy black gilt dial like this 
Photo from Abel, Subexplorer
A truly under the radar watch.
But when it comes on a Tropical Dial, it could look totally different.
Sleek case but with a highly contrasting dial color..
One of the earliest example from 1958
Best,
Sam