Compressor couplings/compressor decouplers acc. to DIN 3489 are used to couple compressed air hoses quickly and economically. They are symmetrical, non-shut-off couplings with 42 mm claw distance (Caution: Risk of getting mixed up with the garden hose coupling with 40 mm claw distance!), which are coupled by twisting the claws with each other. A differentiation is not made between plug and sleeve. As the coupling has no shut-off function, it must be ensured that before coupling the line has no pressure. The danger of decoupling under pressure is reduced with a safety coupling acc. to DIN 3489: when decoupling first the seal is turned back (pressure relief) and then the claws are twisted against each other.