A tantalus, or tantalus cabinet refers to something that holds two or three decanters (occasionally more). The defining feature of a tantalus over other items that hold decanters is that a tantalus has a lock and key.
The tantalus was patented in 1881, and sources do state that it was to prevent the pilfering of the spirits within, either by servants or guests to the household.<source> However it is suggested that this may be an apocryphal tale, and instead the tantalus is an example of the late 1880s era of novelty and technology within the household.
At Tyabb we have a few dealers who have sold tantaluses in the past and continue to have them in stock. Generally all the tantaluses our dealers sell come with the key and an operating mechanism.
Further reading:
"Advertising" The Sydney Morning Herald (NSW : 1842 - 1954) 15 December 1883: 14. Web. 30 Aug 2020 http://nla.gov.au/nla.news-article13549590
"TANTALUS." Melbourne Punch (Vic. : 1855 - 1900) 29 July 1886: 3. Web. 30 Aug 2020 http://nla.gov.au/nla.news-article174568956
"Postscrips" The Daily Telegraph (Sydney, NSW : 1931 - 1954) 28 June 1951: 17. Web. 30 Aug 2020 http://nla.gov.au/nla.news-article248670469