Collar
From LatexWiki - the free latex fetish encyclopedia
A collar is a band fastened round the neck. It may be made of rubber, leather, metal or other materials. If of rubber or leather, it may be embellished with one or more rows of metal studs.
It may be ornamental, a sign of submissiveness, or a fixing point for other accessories such as a leash; in the latter case it may have affixed D-rings. It may be held on with a padlock so that the wearer is unable to remove it.
A very wide stiff collar that prevents the wearer from turning their neck is called a posture collar.