Rear a/c liquid hose for all mid-1978-81 Firebird, Formula, Sprint & Trans-AM. This is the line that connects the front liquid line to the evaporator inlet fitting at the firewall. This is the rear of two hard liquid lines in the system. NOTE - 1978 models used two versions of this line. This version is designed for cars that DO NOT have a low-pressure switch installed on the rear liquid.