The Monkeys' Nuts! 1 Bolt. 2 Nuts. 2 Directions. How does it work?

This is the puzzle Bolt by Scott Eliott. It has some scratches and some wear. Description from Two Brass Monkeys:

A large heavy brass bolt, with two nuts threaded on it. But all is not as it seems this is a fine piece of mechanical engineering that really makes this bolt very, very special. To remove one nut turn it clockwise. To remove the other turn it anticlockwise. If you hold the two nuts and rotate the bolt they each move in different directions. Seemingly impossible as the bolt has the same thread along it's length. This is an impossible object, not a puzzle to solve, but one to ponder on how it was made. Th Monkeys' Nuts! Is, of course, our take on Scott Eliott's Its' Nuts design originally 3D printed by Scott on his SD300 3D Printer. Our version is a very heavy solid brass bolt, the bolt and two nuts weight 1lb or 454g. The bolt is 74mm, the shaft around 22mm in diameter. This thing is big!

Shipping worldwide (incl. USA) from The Netherlands, costs (incl. tracking):

Outside EU: 25€
EU: 15€
Netherlands: 7€

Payment via Direct bank transfer or PayPal. 
*Buyer pays shipping costs and PayPal fees if not paying with F&F, so please wait for the final invoice before payment.

Feel free to message me if you have any questions.