This double mazer is known as a Doppelkopf, which means double goblet. The top was also used as a beaker.
It is made from maplewood decorated with several silver gilded rims and is surmounted by a figure of St. George.
Double mazers like this one are very rare. The Historisches Museum Basel has a similar one in its collection- this goblet is known as the "Luther Goblet".