These thick jelly rings push you up and out. Each ring is tight enough for the perfect amount of squeeze but still comfortable enough for prolonged sessions. Unlike jelly rings. they are thicker. stronger. and more resilient. Made of FLEX-TPR. they stretch up to 5 times their original size. then snap back to their original shape and dimensions. Inside circumference (unstretched) 1 in.. thickness 0.5 in. Steel color.