FLEX-TEND flexible expansion joints from EBAA Iron Sales are designed to protect pipelines from differential movement, including seismic activity, gradual soil subsidence or thermal expansion or contraction. As with any joint capable of expansion/contraction, axial expansion forces will also occur as a result of pressure. The joints can accommodate pressure-induced thrust forces by using an additional water chamber piston that acts in the equal and opposite direction of the imparting thrust, neutralizing the thrust forces. This neutralization of the pressure thrusts allows designers to use flexible expansion joints in applications where thrust blocks or other means of force-restricting devices are not applicable, including bridge crossings, water storage tanks and structures. 800/633-9190; www.ebaa.com.