Some of the vintage watches we rarely talk about from Rolex’s long and illustrious history are their early self-winding fake watches, affectionately nicknamed “Bubble Backs” by members of the collecting world. Although they were not particularly designed for some demanding sport or an inhospitable environment, the Rolex Bubble Back represents the basic, self-winding template that all modern Rolex watches would come to follow. 
Rolex’s Bubble Back replica watches get their nickname from their extremely rounded, protruding case-backs. Although greatly interesting from a design standpoint, the Bubble Back design was actually born out of necessity as an efficient means to house Rolex’s thicker, self-winding movements.
It was during the 1930s that the Rolex first began fitting their watches with automatic movements, rather than the manually wound calibers that had been traditionally used in their watches. The addition of the oscillation weight significantly increased the overall thickness of the movement and required extra clearance for the rotor to move freely inside the case. Rather than making the entire case of the watch larger, the fake Rolex decided to allow the case-back to protrude in a curved, bubble-shaped fashion.
By today’s standards, the replica Rolex Bubble Back watches are rather antiquated in design. Case diameters are relatively small and typically hover around 30 mm to 32 mm for the classic men’s models. Besides, because of their domed acrylic crystals and convex, protruding case-backs, Bubble Back watches are disproportionally thick in an almost egg-like fashion.
Although their large, dome-shaped case-backs have earned these watches several different nicknames all over the years, the “Bubble Back” name is probably the most well known and commonly used today. The small case diameter and relatively large overall thickness combine to make a somewhat awkward and strangely proportioned, egg-shaped watch; however, Bubble Backs represents an early and important time in Rolex’s history, when the company was first starting to refine their self-winding watch movements.
Nowadays, all Rolex fake watches are fitted with automatic-winding calibers; however, they can trace their root DNA back to the original Bubble Back watches that Rolex first introduced during the early 1930s. Almost every watch that the Rolex replica now makes has the word “Perpetual” printed on the surface of its dial, and it was these early Bubble Back replica watches that were the first to receive the Rolex’s inaugural, self-winding movements.