I work in a funeral home, and one day I was looking at the big clunky casket keys no one likes to use and it reminded me of the Rene Magritte painting: The Treachery of Images, the one with a painting of a pipe and the words "This is not a pipe" in french.
A casket key is basically a fancy hex wrench that you use to seal a casket before burial. Like most things in the funeral industry, style does matter and a very basic, functional tool is made to look pretty, even if the families don't usually notice us using it. www.Funerals360.com has a nice article on casket terminology here.
This particular model of casket key is large, heavy, and annoying. It eats pocket linings. It's pretty, but I prefer the smaller plastic handled ones that are nice and light. Or the casket key I made myself pictured here.