The #8244 is the inner section of tubing that goes in and out of the motor as the hand control is depressed.  Older motors have a plastic connector that threads into the outer end of this tube; this part has the clevis pin going through it that attaches the tube to the chair.  The plastic connector tended to break, so Dewert made the decision to lengthen the tube from its original size, and to put two bronze bushings into the tube that the clevis pin could go through.  In effect, they eliminated the plastic connector.  If you have this type of plastic connector on the outer end of the tube, then the #8244 stroke tube is the part you need; you simply unscrew the old tube out of the outer tube of your actuator, and replace it with this new tube, put the clevis pin in, and you are back in business.  If your motor has the new style tube as pictured, all the above explanation about the plastic outer connector does not apply to you; you would only need to replace this part if your old tube had somehow gotten bent or the inner part of the tube was stripped from the spindle nut inside the actuator.  NOTE: this part has caused the most confusion of any part that we have ever sold.

There is a plastic spindle nut (part #8248) inside the actuator tube (where you can’t really see it).  The worm screw goes through the middle of the nut, and the nut has threads on the outside that the stroke tube screws onto; as the motor turns the worm screw, the nut rides up and down the worm screw, pushing and pulling the stroke tube and making the chair go up and down.  This spindle nut is not included with the #8244 stroke tube.