The purpose of this project was to develop a highly flexible sub-ischial prosthetic socket with assisted-vacuum suspension for highly active persons with transfemoral amputation. The Specific Aims were to A1. Develop a highly flexible socket with sub-ischial trim lines A2.Develop durable liners and sealing sleeves A3. Developidentify an appropriate vacuum pumpA4. Evaluate system performance with military amputees and A5. Develop education materials. We completed all tasks, including supplemental tasks related to building and testing the hybrid vacuum pump, year 6 observational study to assess effect of interface components on weight bearing, and dissemination of the technique to certified prosthetists via hands-on workshops.