Mechanical movements are not what the battery is, not electronics, just mechanical parts. It uses a spring to push a series of gears that control the balance of a wheel that rotates and reels at high speeds (up to 36,000 avs / hour).
Almost all high-end watches replica watches are mechanical and require much precision to be weight-built and. Swiss is the most famous and most respected producer of mechanical watches, but there are in Japan as a citizen and Seiko manufacturers that are unsurpassed.
Mechanical clocks can be a wound arm or a self-winding machine (automatic machine), by its nature its mechanical mechanical movement clock will not be so precise quartz look.
Depending on the Mechanical Movement class, it may be reasonable to fake rolex expect that mechanical clocks will work +/- 5-20 seconds per day. The cold and warm temperatures that may occur during transportation may affect the timing temporarily upon arrival.