We also make our own. We have a large customer who uses these exclusively and we used to make hundreds a year for them when houses actually went on the market to be sold lol. Since listing volume has been low the last few years we have just been using existing stock (we also install and remove them). They are very easy to make once you get a system set up and all you need is 1.5 4x4x8 treated posts, single nut and bolt, and two eye bolts. Throw in a shim after a few years of in/out when the joint loosens, they last forever.