This is a fitted case for a generic Chinese-made 0=1" dial indicator with a 9.5mm (3/8") shank and 60mm dial. These are sold on eBay and Amazon for well under $20, but come packed only in a simple foam "brick" unsuitable for storage in the average toolbox.

This case was designed to offer protection and convenient transportation of this inexpensive but very useful measuring tool.

UPDATE! Added Modified_Fitted_Dial_Indicator_Case.stl to the file list. This one provides accommodation for the Harbor Freight version of this tool, which has a slightly larger loop on its rear face than the "generic" version. (With thanks to blingster for posting the details!)