Air & Hydraulics Systems has announced that all butterfly valves, diaphragm valves and “S4” type ball valves will now be supplied with a locking mechanism at no extra charge. Also available is a complete range of lockable ball, butterfly and diaphragm valves, from Austrian Thermoplastic valve manufacturer, Praher Valves GmbH. Praher’s patented locking mechanism permits the operator to select either the open or closed position of the valve and secure it in that position with the aid of a padlock or similar locking device. In the case of the butterfly and diaphragm valves, the hand lever/hand wheel may be locked in open, closed or a variety of increments in between. Praher “S4” Ball valves are rated to 16bar, are double union type and available in sizes from DN10 to DN100. Butterfly valves are available in sizes from DN80 to DN200, diaphragm valves from DN10 to DN125. Both are rated to 10bar. Praher ball, butterfly and diaphragm valves are also available with pneumatic or electric actuators, proportional controllers, and position indicator switches if required.