Box by Edward Kienholz, from photos supplied by Jo Baer.

Inside is the plaster cast from Jo Baer's skiing injury in 1960.

Read 'Edward Kienholz: A Sentimental Journeyman, 1968' online. 
This article was published in Art International 12 (April 1968) 4, pp. 45-49. This was written in response to a (friendly) dare by Kienholz. Baer based her commentary on the words and numbers that were legible in the works displayed. Link to the article