A gripping arrangement for gripping casing is both sufficiently flexible to conform to said casing and substantially inelastic. In a preferred embodiment the gripping arrangement comprises a sheet of zircon paper bonded to a flexible metal carrier plate which has side flanges which fit into an arcuate recess in a jaw holder and bear against the ends of an arcuate pad of resilient elastomeric material. In use, radial forces are applied uniformly through the arcuate paid whilst circumferential forces are transmitted through the flexible metal carrier plate and the side flanges to the arcuate pad and thus to the jaw holder.