HP 1310A Display
Coming up on eBay today: https://www.ebay.com/itm/HP-1310A-Display-19-x24-for-Mainframe-Racks/353381630171
Desk-top mounting described at: http://www.hpmuseum.net/display_item.php?hw=756
And thanks to the HP Museum for the manual: 01310-90908_1310B_OperatingAndServiceManual_134pages_Nov81.pdf
Talk about big! Rack mounted in portrait orientation. X/Y/Z BNC inputs. Electrostatic deflection. P31 phosphor.
Actual viewing area is 11x15” in a frame that is 16.6 x 19.5”. When rack-mounted with flanges that becomes 18.87 x 21” (12U).