The Fetters line is manufacturer for and distributed by Mr. S Leather and Fetters. Originally manufactured in the UK, they are now made in the US. The originals had fully welded hinges and were made of a shiny hard steel. The newer ones are not welded at the hinges and are of a softer (easier on the skin too) powder coated iron. They are made from 1.5" wide 1/8" thick strap iron. The hinges are rolled from the straps rather than separate. The locks are typically an allen wrench bolt in one side which screws into a nut on the other side. The key is distinctively cross shaped with a short allen key as the long extension.
The Pre-18th century design is based on historical patterns from the UK and europe. Simple and chunky.