Your basic collar. This ones locks by placing a padlock through the hole in the locking post. This post holds the two halves together. The collar has four individual chain links sticking out of one face. These can be attached to more chain permanently or with padlocks. The collar is rather industrial in look and surprisingly lightweight since (much like the rest of Martin's line) it is made out of aluminium. Each is individually made by the German machinist Martin and, yes, they are available for purchase. Prices and conditions are available by email.