Abstract: In a cable lock and seal device a roller is rotatable about a single axis normal to the axis of an inextensible member and with respect to a ramp which, in turn, is inclined with respect to the axis of the inextensible member. The roller is moveable up and down the ramp between a retracted position in which the member can be drawn through a passage in which the device and a locking position in which the roller rolls up the ramp to clamp the member against movement in the opposite direction with the member trapped between the roller and the opposite face of the passage. A spring acts on the roller to urge it up the ramp at all times.