squeezing of the gasket 20 to a proper amount is offered by the rib 18 a trapped within the groove 10 a or more accurately the abutment of the portion 18 a u2032 against the upright wall of the groove 10 a the coupling substantially as so far described is readily useful for connecting two pipes of equal or even unequal diameters as depicted in fig6 and 7 where similar reference numerals are used to denote already identified parts and components as illustrated pipe 110 includes circumferential grooves 110 a and 210 a bolts 114 and 214 form a grip around the ring 118 when tightened as clearly seen two couplings are employed in a u201c face to face u201d engaging relationship hence the left hand side pipe 110 is assembled with mounting split ring 118 gasket 120 and mounting flange 122 which is tightened to flange 222 surrounding split ring 218 and gasket 220 rather than to the fixed flange 12 as in the previous embodiment thus the pipe 110 becomes sealingly connected to the pipe 210 several modified embodiments will be now described demonstrating the versatility and other advantages of the present invention referring to fig8 there is exemplified a gasket 320 provided with a thin flap or tongue 320 b designed to be inserted into slot 318 e of the split ring 318 the positioning of the flap between the ring sections will add some flexibility that will compensate for any deviation of measurement or.