The above products are part of a device found at the end of an air line that connects to another air line. You will find glad hands used in the tank trailer business and also on railroad cars. The term glad hand was created because to connect the air lines these two hands will connect or shake hands, similar to a politician out glad handing his voters. The two glad hands are connected by placing them together at right angles and then twisting them to form a straight line. To remove the air line, the two glad hand assemblies are simply twisted back to a right angle.