Core ballstretcher best feature is the outer ribs for super long springy-stretch it stays taller on your sack with more padded grip in the middle for a fatty bag-squeeze. Core fits your nuts with a smooth hourglass inner sleeve on your nutbag... This slick tunnel wraps your sack with a medium firm squeese while the outer ribs keep your stretched down for real low-hangers. Made with extra-soft plus-silicone blend, it'll keep the grip enough with a smooth velvety rubbery comforable stretch, and the right slippery grip for more play. Core ballstretcher has more squeeze inside core has springy ridges outside for more push-down hourglass inner shape grips more when you need thicker rubber rim will not dig into sack measurements: length: 2 5 cm width: 2 5 cm outer circumference: 7 18 cm