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Claim 1

A FLUID EXTENSIBLE DEVICE INCLUDING RELATIVELY AXIALLY MOVABLE MEMBERS, ONE OF SAID MEMBERS PROVIDING AN OUTER AXIAL REDUCED PORTION THEREIN, TWO ADAPTERS MOUNTED IN SAID REDUCED PORTION, SAID MOUNTED ADAPTERS PROVIDING AN OUTER SURFACE WHICH EXTENDS BEYOND SAID ONE MEMBER TO BE IN SLIDABLE BEARING CONTACT WITH THE OTHER OF SAID MEMBERS, A SEALING MEMBER INTERPOSED BETWEEN SAID ADAPTERS IN SAID REDUCED PORTION TO PROVIDE AN ASSEMBLY, SAID SEALING MEMBER IN CONTACT WITH THE OTHER MEMBER TO PREVENT THE BYPASS OF PRESSURE FLUID BETWEEN SAID RELATIVE AXIAL MOVABLE MEMBERS, A WIPER MEMBER INCLUDING OPPOSITE SIDES MOUNTED ON THE OUTER SURFACE OF ONE OF SAID ADAPTERS, ONE OF SAID OPPOSITE SIDES OF SAID WIPER MEMBER IN CONTACT WITH THE OTHER OF SAID MEMBERS TO PREVENT THE PASSAGE OF SUSPENDED FOREIGN SOILDS IN THE PRESSURE FLUID TO SAID SEALING MEMBER AND SAID ADAPTERS, A FLUID PASSAGEWAY EXTENDING FROM AN END OF ONE OF SAID MEMBERS TO SAID OUTER SURFACE OF ONE OF SAID ADAPTERS, AN AXIAL GROOVE IN SAID OUTER SURFACE OF ONE OF SAID ADAPTERS EXTENDING BETWEEN AND PROVIDING FLUID CONTACT TO SAID SEALING MEMBER AND SAID WIPER MEMBER, SAID GROOVE BEING CONNECTED TO SAID PASSAGEWAY, A FILTER MEANS INTERPOSED IN SAID PASSAGEWAY BETWEEN SAID ONE MEMBER AND SAID ADAPTED, SAID FILTER MEANS TO PREVENT THE PASSAGE OF SAID FOREIGN SOLIDS THROUGH SAID PASSAGEWAY; SO THAT THE FILTERED PRESSURE FLUID PASSING THROUGH SAID PASSAGEWAY TO SAID GROOVE SUBSTANTIALLY EQUALIZES THE PRESSURE ON SAID OPPOSUITE SIDE OF SAID WIPER MEMBER, AND FURTHER EXPANDS SAID SEALING MEMBER INTO INCREASED CONTACT WITH THE OTHER OF SAID MEMBERS.