Automatic watches are mechanical timepieces that wind automatically with the movement of your wrist. The movement of your wrist moves the rotor and gives the caliber energy. There is a vast choice for every taste and budget. Base calibers from ETA or Sellita often power the less expensive automatic models, while the higher-priced automatic watches will have developed their own in-house movements. Three of the most famous watch brands, Audemars Piguet, Patek Philippe, and Rolex, use their own calibers and produce their watches almost entirely in-house.