In Geneva on May 15, Sotheby’s is scheduled to auction off this one-of-a-kind Panerai Luminor Prototype produced in 1955.

Made for the Italian military and featuring a Rolex movement, the perfectly patina’d timepiece is an important piece of Panerai and watchmaking history.

And as such, it will run you about $400,000, should you decide you have to have it.

Which would of course be totally understandable, even if your accountant doesn’t agree…