These hardwood cabinets were typically 2' (0.6m) tall and 1' (0.3m) wide an had two doors its front side. Behind these doors was a crystal-lined interior. When the cabinet was in use, this crystal would glow a deep green hue.
Similar to furnace helms, cabinets worked by drawing the magical energy from magical items, draining their charges. Upon uttering the cabinet's command word, 50 cubic yards of breathable air (45.7 cubic m) would be produced. A second command word could be linked to the cabinet to fully restore a spelljammer's air envelope, though this would drain more energy from a given item.