Abstract: A quick-action coupling, in particular for refrigerant lines, is provided with a sleeve (1) and a nipple (2) which can be pushed thereinto, with a set of seals (5) having at least one seal (6) of elastomeric material. It has furthermore a locking device (10, 11, 15) for the coupled position between sleeve (1) and nipple (2), which locking device has a bead (15) on the nipple (2) projecting in particular radially outwards and a cage (10) mounted in the sleeve (1), with retaining fingers (11) which can be opened out and engage behind the bead. A releasing tool (25) for opening out the retaining fingers (11) of the cage (10) is provided, which tool can be fitted onto the nipple (2) and can be pushed in in the direction of the sleeve (1). There is provided on the outer circumference of the sleeve (1) a radially outwardly projecting border (30). The releasing tool (25) had a radially inwardly directed collar (29), serving as a stop.