Dandong Movement Factory, also known as Liaoning Watch Factory, is one of China’s oldest and most respected watch manufacturers. Founded in 1957 in Dandong, Liaoning Province, the factory has produced over 40 million watches of various types. Among them was the famous Peacock brand, once considered a dream watch for many Chinese consumers. The factory also developed its own mechanical movements, such as the SL series, which have been widely used by both domestic and international watch brands.
One of Dandong Factory’s most remarkable achievements is the development of the Dandong 4130 movement — a clone of the Rolex Daytona Caliber 4130. The Rolex Daytona is a legendary chronograph with a long history and an outstanding reputation. Introduced by Rolex in 2000, the Caliber 4130 replaced the earlier 4030 movement, which had been based on a modified Zenith movement.
The 4130 is a self-winding chronograph movement featuring a column wheel and vertical clutch system. It beats at 28,800 vibrations per hour and offers a 72-hour power reserve. It also uses a Parachrom hairspring for improved shock and magnetic resistance, along with the Paraflex shock absorption system to enhance stability and accuracy. The 4130 is widely regarded as one of the finest chronograph movements ever made — and also one of the most difficult to replicate.
However, Dandong Factory accepted the challenge and successfully created the Dandong 4130 movement, officially known as the SL4510. The SL4510 is an extremely faithful reproduction of the original 4130, sharing nearly identical structure, dimensions, functions, and appearance. Even the engravings on the bridges and plates closely resemble those of the genuine movement. The primary difference is that the SL4510 uses certain Chinese-made components instead of Swiss-made parts, including jewels, screws, springs, and shock absorbers.
The Dandong SL4510 movement was first introduced in 2018 by Noob Factory, one of China’s most famous replica watch manufacturers. Noob used the SL4510 in its Rolex Daytona replicas, producing watches that looked remarkably close to the genuine models. Daytona replicas powered by the SL4510 quickly earned praise among replica watch enthusiasts for their precision, reliability, and durability. The SL4510 was later adopted by other well-known factories and brands, including Clean Factory and BT Factory.
Compared with other Chinese-made chronograph movements commonly used in Daytona replicas — such as the Shanghai 7750 and Dandong 7750 — the SL4510 offers several significant advantages. Both the Shanghai 7750 and Dandong 7750 are based on the ETA 7750 architecture, another famous chronograph movement originally developed by ETA in Switzerland in 1973. The ETA 7750 uses a cam-operated chronograph mechanism and a horizontal clutch system, runs at 28,800 vibrations per hour, and provides a 42-hour power reserve.
The main differences between the SL4510 and the Shanghai/Dandong 7750 movements include:
- The SL4510 uses a column wheel mechanism, which delivers smoother and more precise chronograph operation compared to the cam-operated system found in the Shanghai/Dandong 7750. The column wheel also produces a more satisfying click when operating the chronograph pushers.
- The SL4510 features a vertical clutch system, eliminating the seconds hand stutter commonly seen when starting or stopping the chronograph on horizontal clutch movements. The vertical clutch also reduces wear on the chronograph gears and improves overall timekeeping accuracy.
- The SL4510 provides a longer power reserve than the Shanghai/Dandong 7750 — 72 hours versus 42 hours. This allows the watch to continue running for a longer period without winding or wearing.
- The finishing on the SL4510 is superior. It features more polished and beveled edges, more decorative engravings, and a greater number of blued screws.
In conclusion, both Dandong Movement Factory and the Dandong 4130 movement represent major achievements in the history of Chinese watchmaking. They demonstrate that China is capable of producing high-quality mechanical movements that can compete with — and in some aspects even surpass — certain Swiss-made movements. At the same time, they provide replica watch enthusiasts with an excellent alternative, allowing them to enjoy the aesthetics and performance of the Rolex Daytona without paying the enormous price of the genuine watch.
