A white cane is used by many people who are blind or visually impaired. Its primary uses are as a mobility tool and as a courtesy to others, but there are at least five varieties, each serving a slightly different need. Long Cane: This "traditional" white cane, also known as a "Hoover" cane, after Dr. Richard Hoover, is designed primarily as a mobility tool used to detect objects in the path of a user. Cane length depends upon the height of a user, and traditionally extends from the floor to the user's sternum. Some organisations favor the use of much longer canes. Guide Cane: This is a shorter cane - generally extending from the floor to the user's waist - with a more limited mobility function. It is used to scan for kerbs and steps. The guide cane can also be used diagonally across the body for protection, warning the user of obstacles immediately ahead. Identification Cane (or Symbol Cane in British English): The ID cane is used primarily to alert others as to the bearer's visual impairment. It is often lighter and shorter than the long cane, and has no use as a mobility tool. Support Cane: The white support cane is designed primarily to offer physical stability to a visually impaired user. By virtue of its colour, the cane also works as a means of identification. This tool has very limited potential as a mobility device. Kiddie Cane: This version works the same as an adult's Long Cane but is designed for use by children. Green Cane: Used in some countries to designate that the user has low vision while the white cane designates that a user is blind. Mobility canes are often made from aluminium, graphite-reinforced plastic or other fibre-reinforced plastic, and can come with a wide variety of tips depending upon user preference.