Purlin Kit for Hobby Greenhouse KitTruss Support Kit for DIY Hoop House This kit gives growers a simple way to reinforce long greenhouse spans with a top rail truss system. It uses locally sourced 1 3 8 inch top rail along with the included brace adapters, tension bands, and hardware. Once assembled, the truss creates a strong center support that helps reduce sagging and adds stability in wind and snow. Features Adds a strong center support to reduce sagging across long greenhouse