A range of line markers to help you navigate overhead environments when visibility drops. Guidelines are used in caves and wrecks to help you navigate back to the entry point if visibility drops to 0. Line arrows always point towards the closest exit and are shaped like a triangle that you thread over a line to feel you way out. Cookies mark a specific point of interest without confusing other divers. Use these to communicate with your team without disrupting other teams on the line. REM, or Reference Exit Markers, are non-directional markers that can be used to write messages to your team at points on the line.