AMERICAN DREAM PRODUCTS-Knobs for Needlework Frames: Oak 4pk. Used to hold scroll rods tightly in place to prevent them from unrolling while you work. Knob with threaded bushings guaranteed not to strip. This makes the frame interchangeable for use again and again for other projects. Measures: 1-1/2x1-1/2x3/4 Inch. Made in USA.