Designed by Crowsfoot Studio to fit the Snapdragon Frame and most 360 degree frames or hoops. Allows the frame to rotates 360 degrees on a nylon ball which will allow easy movement with no squeaking. Swivels forward and sideways for a variety of working positions. Easy tightening knobs to keep in position. Fits under your thighs for stability and with the knobs being on top, will prevent bruising. Made out ash. Made in Canada