Abstract: A gas spring has a single bypass across the piston that is controlled by a valve member of an elastomeric material, which restricts flow through the bypass when the gas spring is compressed (piston rod moving into the cylinder) and produces a pressure differential across the piston that varies inversely with temperature. The increasing force opposing compression of the gas spring due to the pressure differential across the bypass as the temperature of the gas spring, and thus the output force, decreases maintains the handle load more even over a range of temperatures. The elastomeric valve member has very little effect on the normal operation of the gas spring in the extension (rod moving out) mode.