The Big "O" ? The perfect cylinder "o" shape Features: super comfortable For maximum pleasure and comfort, use with water-based lubricants only The latest glow in the dark technology Immerse under bright light or in sunlight before use to ignite the glow effect only use with water-based lubricant Clean with anti-bacterial soap and water Sila-Flex is a premium, phthalate-free hybrid silicone with an ultra smooth and soft finish durable, unscented and extra stretch, while retaining the original shape.