Balluff, germany, manufactures strokemaster inductive cylinder switch for piston position feedback in hydraulic cylinders. Features include: pressure rated to 207 bar [3000 psi]; magnetic field immune, for use with welding equipment; available in dc or all current [ac/dc] versions; easy installation, no threaded hole is required in the cylinder; sealed directly at flange, connector can be oriented after installation; and they are available in various lengths for different cylinder sizes.