The Low-altitude Escape Harness is a piece of equipment used by International Rescue in Edge Of Impact. Its purpose was to rescue two trapped men (Jim and Stan) from the top of the British Telecom Tower.
The Booster Mortar is used to fire the two capsules which contain two low-altitude escape harnesses (one in each).
The jetpack is worn on the back, and when the pin is pulled, launches the person wearing it up into the air. They will then have a slow, safe descent to the ground.