Nurge high-quality Spring Tension embroidery hoops consist of a strong colored plastic outer hoop, and a sprung metal inner hoop. They come in 3 sizes: Large 7.7" (195mm), 9mm deep (excluding the handles. Medium 5" (126mm), 7mm deep, excluding the handle. Small 2 1/4" (58mm), 5mm deep, excluding the handle. Each come in a variety of colors, Green, Blue, Yellow, Red & Black and are sold in a single size and color. The Nurge spring hoop can be used for hand or machine embroidery as the slender design makes it easier to place the ring under the freehand foot of the machine. The strong spring keeps your needlework projects taut and under tension. Super easy to use, spring tension hoops eliminate the need to tighten screws, but can be quite firm as they need to keep the fabric taut. Lay your fabric over the outer hoop. Give the inner hoop a squeeze and gently set it inside the outer hoop.