A belt worn by Starfleet landing parties in the animated series that surrounds the wearer with a glowing personal force field holding in air, warmth and pressure.
The life support belt is introduced in Beyond the Farthest Star, the first episode of The Animated Series, when Kirk and his officers board an ancient derelict pod ship in open space. Instead of pressure suits they wear slim belts that project a yellow-green aura around the body.
The field allows free movement and normal use of equipment in vacuum, under water or in poisonous atmospheres, and it appears throughout the series, including The Slaver Weapon, where Kzinti captors strip the belts from their prisoners.
The belts are not invulnerable. They can be removed or switched off by an enemy, and their power is limited. They are not seen in the live-action productions, where environmental suits remain standard.