From Doc Johnson, This classic circle shape has an additional knob that applies pressure behind the scrotum for an ultimate climax. The Mega Ring's phthalate-free, body-safe, glow-in-the-dark material keeps the bedroom aglow as long as you last.Approximate Product Dimensions: C-Ring, Width/Diameter: 2 in. (5.1 cm), Unstretched Inner Diameter: 0.9 in. (23 mm), Depth: 0.7 in. (18 mm)