An automatic watch works as long as it is worn. There may be a reserve power of about 24-48 hours. But then they tend to stop completely due to lack of wrist movement, unless they are kept in a watch-winder. This is an important issue, especially for collectors' items and high-quality designer watches with complicated settings. SGWATCHWINDER watch winder keeps self-winding watches going by means of rotary and/or vibration technology. In fact, SGWATCHWINDER watch winders actually emulate arm movements. This ensures that the watch is always operational with the right time, the right date, and the right moon-phase, etc. The more complicated a watch is, the more time and effort it takes to reset. Anyone who owns several automatic watches will appreciate the sheer luxury of SGWATCHWINDER watch winders.