an automatic movement is mechanical movement with a self-winding
design. An automatic watch harnesses the energy produced by motion to
wind the spring. This movement features a rotor that spins when the
watch is in motion as when the wearer moves his arm. The mechanism
transfers the energy from the spinning rotor to the main spring of the
watches have all of the advantages of mechanical watches--detailed
construction, durability--plus the owner does not need to manually wind
the timepiece frequently. If you wear the watch every day, it will
maintain its power reserve.
drawback to mechanical and automatic movements is that they can gain or
lose a few minutes per month; thus, an owner should check these
watches once or twice a month and adjust the time.