From Halopedia, the Halo wiki
Anti-gravity chairs, or antigrav chairs, are Covenant personal conveyances that serve as the primary form of transportation for the San'Shyuum. The Hierarchs' luxurious anti-gravity chairs are also known as gravity thrones. Anti-gravity chairs descended from wheeled chairs used by San'Shyuum elders prior to the firing of the Halo Array.
Due to their frail physiology, the San'Shyuum make their lives more comfortable by using levitating chairs for transport instead of walking. The majority of mature San'Shyuum use anti-gravity chairs of varying kind. They are controlled by holographic control panels located in the armrests. These panels also function as holographic projectors. San'Shyuum often wear an antigravity belt under their robes as a secondary support mechanism should they choose to leave their chair.
Their comfort and vertical anti-gravity propulsion capacity is directly proportional to the San'Shyuum's status and rank; the chairs used by Junior Ministry staffers need to combine their anti-gravity fields by linking arms and traveling in tightly-packed "commuting rings" of twenty or more when crossing longer distances. Senior staffers can manage to travel in groups as small as seven, while the sophistication of Vice Ministers' chairs allows them to commute in trios. Only full Ministers and higher are permitted to use sufficiently powerful units for individual flight. The ascetic priests used simple chairs made of stone as a reflection of their austere lifestyle.
Anti-gravity chairs become more powerful and better-equipped as the San'Shyuum's rank increases. In the rare event that a Hierarch comes under threat, their gravity thrones are equipped with dual assault cannons, which can make short work of even well-armored assailants. The throne also projects an energy shield that is virtually impenetrable to all small arms fire, although the Prophet is still vulnerable to melee damage. The Hierarchs' gravity thrones also possesses a short-range teleportation capability.
While predominantly used by the San'Shyuum, some shipmasters also use a form of anti-gravity chair as command chairs onboard warships. These chairs are considered less luxurious versions of the gravity thrones used by the Hierarchs.
List of appearances