First two numbers — Designates air terminal diameter
Second two numbers — Designates air terminal length
Prefix A — Designates Aluminum
Prefix C — Designates Copper
Suffix ST — Designates Safety Tipped
Suffix X_ _OS — Designates offset in point

Field bends are permissible but must not exceed 90 degrees or have a radius of bend less than 8 inches.

Example:

Air Terminals are made of solid Aluminum or Copper in one solid length, off set to your specifications. Please provide your exact requirements.