Abstract: The present invention relates to a downhole pressure equalizer comprising an elongated housing comprising a piston compartment having a first end provided in fluid communication with an outside of the elongated housing and a second end provided in fluid communication with a process chamber of a well tool. A piston device provided in the position compartment comprises an outer piston section slidingly and sealingly engaged with the piston compartment; and an inner piston section slidingly and sealingly engaged within the through bore of the outer piston section.