Collars forged from various metals and alloys are worn by all the various military personnel of the Commonwealth as a token of their service to the Masters and their God Emperor. Since metullurgy is a science that the Masters keep secret to themselves, only the Masters can remove them. Thus they become a form of enslavement, since the Law of the Masters mandates that anyone found wearing a service collar outwith their proper duties can be subject to terrible punishment.

Service collars bear at the throat a boss which depicts the cypher particular to the organization to which they belong - whether it be a legion, watch-tower, ship etc. To either side of this boss are a number of sliders indicating information such as rank and time of service.

Sliders on one side of the boss will show rank and insignia: on the other the number of years that the wearer has been in service.

The first diagram shows a collar that would either be worn by an auxiliary squadron commander or else an Ichorian commander of twenty. The second diagram shows the collar worn by the auxiliary commander of a watchtower.

The third diagram shows some of the sliders used to show rank: a spot ring (1), a bar (5), a mual or zero ring (0). The fully loaded collar shows the insignia for a huimur quartermaster of the Ichorians.