This mysterious weather predictor has been used since 1750. After 250 years, how it works is still a mystery, but it is believed that it has to do with the electromagnetic changes caused by weather and sun storms. The appearance and changes of the crystals inside indicate changes in the weather. Packaged in a handsome velvet-lined black box with brass mounting accessories. Includes the base, self tapping screw, finial and mounting accessory to enable either wall or table top fixed mounting. See the coordinating Stormglass Display Panel for a truly unique combination!