fig1 shows a perspective view of an embodiment of the present invention . upper support unit 10 includes a standardized male connector 12 , which is well known in the art . a grease insertion port 14 is shown on one side of upper support unit 10 . another grease insertion port 15 ( not shown ) is on the opposite side of the grease insertion port 14 . a set screw can be sealed in place in each grease insertion port after the desired amount of grease has been inserted into the internal valve and cylinder system discussed below . a piston 16 is shown protruding from the bottom of the upper support unit 10 . another piston 17 ( not shown ) is located parallel to and on the opposite side of the upper support unit 10 from piston 16 . a valve control button 18 is shown on one side of upper support unit 10 . this button 18 is connected to a valve control shaft 20 that is internal to the upper unit 10 and thus not shown in this figure . referring again to fig1 , a lower support unit 22 includes a standardized female connector 24 ( not visible in this view ). set screws , placed in openings 26 , are usable to secure the unit to another connector similar to connector 12 of a unit to which the present invention may be attached . lower unit 22 includes a first bridge portion 28 through which a rotation axis pin 30 may be passed . a second bridge portion 29 is located on the opposite side of the lower unit 22 parallel to the first bridge portion 28 . upper unit 10 includes a rotation through hole 32 , which provides a clear path for the pin 30 to pass . when assembled , pin 30 is passed through bridge 28 , hole 32 and bridge 29 and secured in place with securing mechanisms 34 and 35 ( not shown ). fig2 a - 4f show a series of views of an exemplary embodiment of the present invention . fig4 b shows a side cut - away view of the assembly . note the valve control buttons 18 and 19 connected to valve control shaft 20 . shaft 20 includes a port 40 and seals 42 . upper unit 10 includes a bored out diameter 44 on one end that is large enough that valve control button 19 may be pushed in toward the center of the assembly . this will cause the valve control shaft 20 to slide within a through hole 46 within which shaft 20 is located , such that port 40 is aligned with valve ports 48 and 49 shown in fig4 e . fig4 e is a side cut - away view of the assembly perpendicular to the view of fig4 b . thus , shaft 20 is located in hole 46 of fig4 e . as discussed above with reference to fig1 , a volume of grease is forced into grease entry ports 14 and 15 , which ports are subsequently sealed . the volume of grease fills the internal area , which is under vacuum , in this embodiment . pistons 16 and 17 are located within cylinders 50 and 51 respectively and include seals 52 . when button 19 is pressed up against the stop of bored out hole 44 , shaft 20 slide such that port 40 aligns with ports 48 and 49 . in this position , which is referred to herein as the “ unlocked ” position , the pistons can move up and down in the cylinders . for example , when piston 16 moves up in cylinder 50 , the constant volume of grease forces piston 17 down in cylinder 51 . when button 18 is pushed , it forces shaft 20 to move such that port 40 is no longer aligned with ports 48 and 49 . in this position , which is referred to herein as the “ locked ” position , force applied to either piston will not move that piston because the grease cannot flow within the system . the assembly can be attached to a prosthetic , placed in the unlocked position , the angle is adjusted between the upper unit and the lower unit , and then the assembly is locked . in practice , e . g ., a practitioner or user could attach the assembly to a prosthetic ( prosthesis ) and the end user could place it in the unlocked position . the user could then adjust the angle between the upper unit 10 and the lower unit 22 so that the assembly was comfortable . the user could then place the assembly in the locked position to hold it in the desired alignment . the present invention can be made in a variety of ways . examples of suitable materials are metals ( e . g ., aluminum , titanium ) and plastics . the invention can be machined or cast the following is a description of a machining method . in the first step , the raw material is placed into a cnc lathe . material is removed to form a straight diameter and a spherical radius on one end of a shaft . a parting tool separates the part from the bar stock . in the second step , the part is placed into a fixture in a cnc milling machine and is held by the straight section that was produced in the first step . material is removed by use of an end mill cutting tool to create two straight sections , leaving a solid body of material extending from one side of the round stock to the other side . two holes are then drilled from the top of the part to form the piston chambers . the bottoms of the holes are then flattened by means of a drill - type cutting device . a hole is then drilled on the flat surface at the bottom of the piston chambers to connect to a hole to be drilled perpendicular to the piston chamber at a later time . a boring tool is then used to size each piston hole to a + 0 . 0015 /− 0 . 000 nominal diameter of the mating piston . in the third step , the part is then moved in the fixture so that it is held horizontally to be trimmed and gripped by the flat sections machined in the second step . a hole is then drilled into the body of the part to form the chamber used to insert the grease into the finished product . a second hole is then drilled to flatten the bottom of the first hole drilled in this step . this first hole crosses the hole drilled in the bottom of the piston chamber hole described in the second step to allow a connection between these two chambers . a small hole is drilled at the bottom of the grease filled hole to a depth to enter a hole to be drilled perpendicular to this hole in a later step . a high - pressure port tool is then used to create a seal surface for a high - pressure plug ( 14 ′ in fig3 e ) to be installed during final assembly of the finished product the port hole is then tapped to connect with the high pressure plug described above . the part is then turned 180 degrees and this process is repeated . in the fourth step 4 , the part is then moved in a fixture and held perpendicular to the grease fill holes , and timed by the flat sections machined in the second step . a hole is drilled through the material at the end furthest from the spherical radius end of the part machined in step 1 , to be referred to as hole 1 . a second hole is then drilled through the material closer to the spherical end of the part , to be called hole 2 . an end mill cutting tool is then used to remove the remaining rough stock below the spherical radius of the part , creating a raised radial section of material around hole number 2 . a counter bore is then milled into the raised boss of material surrounding hole number 2 . a larger counter bore is then machined into the flat section of material in which hole number 1 was drilled . a corner radius cutting tool is then used to radius the top edge of the counter bore surrounding hole number 2 , the edge of the bottom of the counter bore and hole number 2 , and the bottom of the counter bore and hole number 1 . a reamer is then used to size hole number 1 to a diameter of + 0 . 000 /− 001 of the diameter of a mating pin to be installed during final assembly . a high precision reamer is then used to size hole number 2 to a diameter of + or − 0 . 0003 of a specific size to be used by an additional tool to be used later . a roller burnishing tool is then used to provide a specific diameter of + or − 0 . 0005 to a mating part to be used in final assembly in hole number 2 . this tool also provides a finish to be used as a sealing surface for a series of o rings to be used in the final assembly of the part ; additionally the tool provides for a smooth edge of the hole drilled in the bottom of the grease fill holes , drilled in the third step , connecting the grease fill holes to hole number 2 . the part is then turned over 180 degrees and the above procedures with the exception of drilling , reaming and burnishing of holes number 1 and 2 , are repeated . in the fifth step , the part is then moved in the fixture so that the diameter turned in step number 1 is facing upward . the part is held and timed by the flat sections milled in step number 2 . an end mill cutting tool is then used to cut angular flat sides in a square pattern parallel and perpendicular to the flat sides milled in step 2 and wherein the sides of the square pattern are angled so that the top of the square has larger sides than the bottom . in the last step , the part is then placed in the fixture horizontally so that holes number 1 , and 2 described in step number 4 , are perpendicular to the surface being held , and is timed by the flats milled in step 2 . an end mill cutting tool is then used to cut the bottom end of the part farthest from the spherical radius end in an angular pattern to allow clearance for a mating part to be used in the final assembly . a radius cutting end mill tool is then used to radius the top edge of the profile cut described above . the part is turned over 180 degrees and the radius tool is then run on the opposite side of the profile cut described above . the part is then cleaned and deburred . the foregoing description of the invention has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise form disclosed . many modifications and variations are possible in light of the above teaching . the assembly is characterized as having an upper unit and a lower unit , which characterization is intended to show the relative positions of the two units , but is not intended to limit the usable orientation of the assembly , e . g ., the assembly can be inverted , or used in another orientation without departing from the scope of the invention . the embodiments disclosed were meant only to explain the principles of the invention and its practical application to thereby enable others skilled in the art to best use the invention in various embodiments and with various modifications suited to the particular use contemplated .