A clerical collar, clergy collar, dog collar, or Roman collar, is an item of Christian clerical clothing. The collar closes at the back of the neck, presenting a seamless front. The shirt may have the collar built in. The clerical tab is almost always white and was originally made of cotton or linen but is now frequently made of plastic. Sometimes it is attached with a collaret or collarino that covers the white collar almost completely, except for a small white square at the base of the throat, and sometimes with the top edge of the collar exposed to mimic the collar of a cassock. It may simply be a detachable tab of white in the front of the clerical shirt. The clerical shirt is traditionally black (or another color appropriate to a person 's ministry rank, such as purple for Anglican bishops), but today is available in a variety of colors depending on the wearer's preference. Once the clerical collar is removed the garment is indistinguishable from any other shirt. When clergy are delivering sermons, they sometimes attach preaching bands to their clerical collar.