Abstract: An apparatus for coating a substrate has a vacuum chamber designed to receive the substrate and at least one sputtering target to be ablated during operation of the apparatus by particle bombardment. At least one window is arranged in the wall of the vacuum chamber. A device for determining the wear of the sputtering target, by optically measuring the distance between at least one predefinable point outside the vacuum chamber and at least one predefinable point on the surface of the sputtering target, and including an evaluation device correcting for any parallax offset and/or a geometric distortion.

Abstract: A hose having stable length under pressure comprises an internal leak tightness sheath, and armoring consisting of at least two pairs of layers of helically wound wires, the two layers of the same pair being made of identical wires laid at the same sheathing angle but in the opposite direction, and an external protective sheath. All the wires are laid at one of two sheathing angles, one less than 55.degree. the other greater than 55.degree.; the wires of at least one pair of layers exhibit one sheathing angle between 40.degree. and 53.degree., and the wires of at least one other pair of layers exhibit a second sheathing angle between 57.degree. and 70.degree..