Building fence post sewer hose storage. Need 5.5" caps

I did mine like Barney S did with one exception. My cap is held on by 2 springs, one on each side. I took a cotter pin passed the spring through the center and put it through a hole drilled in the side of the post. Then bent the legs flat against the side (on both sides) then did the same for the cap. This allows 1 handed operation. I just pull the cap out until it clears the post and rotate it under the post. I have had this post on 2 5th wheels for over 50,000 miles and hasn't failed me yet.

I'd get pictures, but it is cold and wet and in storage, and I've got a bourbon drink in hand.