This fine clock from Chelsea, features the most advanced development in accurate timekeeping: the quartz crystal electronic movement, which has specifications to within 3 minutes per year, or.5 seconds per day. This precision clock with 12/24 hour dial is mounted in a box cut from a solid piece of mahogany. which has gold plated brass hardware to prevent tarnish.The movement is protected by a one-piece forged brass case with screw bezel. The easy to read dial is 4.5 inches in diameter, with sweep second hand. Power for one year is provided by one size AA battery. The box size is 6.1x6.1x4 inches, and has a brass engraving plate inside the top. SW 5 lbs.