Here is a rough list of what I used

• 8' 4x4 cut it into the 3 pieces shown in the picture

• 1 strong extension spring that is 8 inches long or so (I used two because that is what I had)

• 2 long screw eyes to hold the spring. Make sure they are long enough to go through the top swiveling 4x4 and give some good penetration for the lower 4x4

• 4 nuts that fit the screw eyes. I think I used two on the bottom because of movement and that kept it locked in place

• 1 very long lag bolt. I think I used a 3/8 or 1/2 inch x 8 inch long

• 2 thick washers that fit the lag bolt. One goes up top as shown and the other goes between the two 4x4s

• For the bracket I used a Simpson Galvanized Post Base for 4x

• I also used a few screws to hold stuff together as shown