French shackles

This is an extremely rare set of leg irons made in France. The seller suggests they may be the precursor of the Manurhin company model. 

The price is $600 or best offer. There is one key for the recessed bolt mechanism. 

UPDATE: These have sold, an offer has been accepted. 

These are very heavy with six large oval links, an O ring at each non-swivelling clevis, and a large O ring in the center for attachment. 

Manurhin was formed in 1919. The full name of the company was Manufacture de Machines du Haut-Rhin. The company was focused on precision machine parts such as automatic lathes, food processing machinery, ammunition manufacturing equipment, firearms, and police equipment for the French Gendarmerie. They gained a reputation for high quality, durable, and precise equipment across all their endeavors.

Below, another French leg iron from Rivolier. The design is very similar; the locking bolt itself may be different. The key seen here is an alloy handcuff key from Hiatts alloy models. Photo from old handcuffs.com

You can see similarities such as the cuff shape, the central O ring and the lock type. Rivolier is a French company founded in 1830 in the Saint-Ettiene region of France, which was also the home of other French firearm manufacturers. They also produced bicycles from 1909 until 1950, and in the late 20th century, partnered with Remington, Sig Sauer, and acquired Verney-Carron, the oldest small arms manufacturer in France. 

Above, a modern pair of Manurhin 1985 high security handcuffs. The tumbler lock serves as a double lock on top of the standard single lock.

Above, detail close up of the high security tumbler lock on the modern Manurhin 1985 model.