The Pivot Base joints are made from super tough nylon. Used in conjunction with a Pivot Arm (J150PA). These joints can be paired with our L-shaped or R-Shaped aluminum tube profiles to create adjustable angles . Eliminates the need for mitering. Easily inserted in the tubing with a rubber mallet. Connections are strong and rigid without the use of fasteners or welding. Fast, secure aluminum frame system for all types of building projects.