The first "official" Martin Rigid Handcuffs - Model S. These cuffs have many enhancements over the initial limited test run (see Martin Rigid Handcuffs. There are TWO keyholes and two double-locks notches. The double locks are activated by pushing them in with a pen or the tip of the handcuff key. The bows are grooved on one side as well. The workmanship and finish are generally excelent with the single problem being that the edges are somewhat sharp. The cuffs themselves are form fitting to such a degree that most people will NOT be able to rotate their wrists in these - further increasing their security. Each is individually made by the German machinist Martin and, yes, they are available for purchase. Prices and conditions are available by email.