Mineral oil is the only nonprescription lubricant. It reduces friction, thus acting as a lubricant, or wetting agent, built into the lens. Colza oil is extensively used as a lubricant for machinery. Graphite powder is used as a dry lubricant. The gas is often mixed with a silicone-based lubricant. Hydrogenation of castor oil saturates the alkenes, giving a waxy lubricant. Water pump seal lubricant is also added. Here, wear is detected by the presence of wear particles in a liquid lubricant. Gear oils account for about 20% of the lubricant market. PDMS is widely used as a condom lubricant. It is used commercially in foods requiring a natural emulsifier or lubricant. These glands secrete mucus and a vaginal and vulval lubricant. The company's first product was a graphite lubricant and applicator for early automobiles. The petroleum jelly served as both a lubricant and a stabiliser. A proper lubricant, typically graphite powder, is essential.