Abstract: A clamp has a split ring with projections extending outwardly from shoulders on the ring. The projections converge towards each other outwardly of the ring and have grooves onto which a nut is threaded. This causes the projections to be moved towards each other thereby closing the gap in the ring, and tightening the clamp. The inward movement of the projections is facilitated by grooves in the shoulders. A rib and projections are provided on the radially inner surface of the ring to facilitate the gripping of a body clamped by the clamp. A strengthening rib and handles are provided on the radially outer surface of the ring. The clamp is simple and secure and can be manufactured cheaply from a plastics material.