sentences:  A hybrid marker, also known as a referencing exit marker or REM, is a more recently developed line marker used as a directional marker by the diver placing it, and seen as a cookie by others.They are rectangular with slots like the arrow and cookie forms for attachment to a line, and have a relatively large blank space on one end to add identification on one side and to write on the other side.Referencing exit markers are asymmetrical so can be used to show the direction which the diver came from.