Silicone-based lubricants are usually formulated with fewer than four ingredients and do not contain any water. Silicone lubricants offer a different feel from water-based personal lubricants. Silicone-based lubricants are not absorbed by skin or mucus membranes, and consequently last longer than water-based lubricants. Many different silicone lubricants are commercially available with varying quality and performance. Not all silicone-based lubricants are certified latex-safe, but silicone-based lubricants have not been shown to increase the risk of HIV transmission during anal intercourse, as some water-based lubes have.