Abstract: A rolling head diaphragm and dome-shaped piston configuration where the geometry of the diaphragm and piston, and the length of stroke, are modified to enable the commonly known rolling wall action of rolling wall diaphragms to be extended into the center section of the diaphragm up over the piston head when it is at the lower end of it's stroke, thus eliminating the right angle of the head/wall juncture of common pistons and the tight radius of the head/wall shoulder molded into other diaphragms, thereby extending the maximum available stroke and improving diaphragm reliability and longevity.