A coupler for use with a sealing member for releasably securing together adjacent ends of grooved end pipe and forming a fluid-tight seal therebetween. The coupler includes a pair of arcuate segments, each segment having a generally inverted U-shaped cross-section so as to define a pair of depending leg portions and an outer spanning wall extending therebetween, each of the coupling segments further defining first and second end portions. The first end portions of each arcuate segment are joined together in a pivotal connection. A closure including a bail pivotally mounted on a release/locking lever, an attachment hook and a pair of abutment surfaces is provided at the second end portions of the arcuate segments for releasably joining and securing together the second end portions of the segments about the sealing gasket and adjacent pipe ends with the leg portions of the segments projecting into the grooves therein.