The stock for all the shafts, the O-rings, the tube for the pressure vessels, and the universal joints. After cutting everything down to size I assembled and tested the pressure vessel to see if there were any leaks using a small trashcan filled with water. The vessel passed the test, but more testing needs to be done at greater depths. I had to widen the holes in the end caps and mounting ribs a little to make sure the shafts went through easily but still snug.  The next step is to get the u-brackets together and assemble the rest of the mechanical design and see if the motors have enough torque to turn the shafts in the rotary seal.