A fire suppression sprinkler adapted to receive arcuate surfaces of a grooved coupling is retainable to the coupling in a pre-assembled state. The coupling joins the sprinkler in facing axial end to end relation directly to grooved pipe. The sprinkler has a monolithic body which defines a bore having an inlet and an outlet. A groove, positioned between the inlet and the outlet extends around the body. A projection, positioned between the groove and the outlet also extends around the body.