A coupling for handling liquids, gases, or a combination thereof characterized by its ability to convey high volumes with low flow resistance through valve elements. The coupling includes a pair of clam shell type valve elements pivotal between closed and open positions by the nose of the male coupling half during coupling of the halves and recesses defined in the valve elements receive the coupling nose so that the engagement between valve elements and coupling nose does not produce a flow restriction. The valve elements are provided with bonded resilient sealing edges and include a homogeneous bumper for absorbing shocks during coupling. A double action latch system is also disclosed having a sequence of operation which significantly reduces the likelihood of inadvertently uncoupling the coupling halves.