Other advancements were also being made to improve the durability of the wristwatch. The faces were replace with ones made of synthetic plastic. This made them much more durable and resistant to breaking and cracking. Another advancement was in the dials. The dials were now being made out of metal.
Another advancement in the wristwatch was the self winding watch. Rolex introduced their self winding wrist watch in 1931. The design must have been good, because it is still being used in wristwatches today.
