Use this hardware to make a stiff arm " to hold your dock in place. The stiff arm " is a system we developed to be used as an alternative to piling to anchor your dock in place. This system is great when you have a single dock that runs parallel to shore. Its self tending and has the ability to rise an fall the distance of the length of pipe you use. For example, if you use a 30' pipe your dock is able to rise 30' and fall 30'.