Ralph Walter 2/27/18
Our source no longer sells these. Amazon has them but they seem quite precious. I don't believe we paid more than $0.25 each...
Jamie Hascall 2/27/18
Slightly different keyhole model, brass plated steel. https://888mfgcorp.com/brassplatedmuseumhanger2x2100pack8902-c.aspx
Bradley Sanders 2/27/18
Try McMaster Carr under "Keyhole Hangers". Many side hangers. This is the only similar piece.
Philip Brutz Mount Maker Exhibition Production The Cleveland Museum of Art 11150 East Boulevard Cleveland, Ohio 44106-1797
T 216-707-2617 F 216-707-6687