Brake fluid is a type of hydraulic fluid used in brake applications in motorcycles, automobiles and light trucks. Brake fluid is used to transfer force under pressure from where it is created through hydraulic lines to the braking mechanism near the wheels. Brake fluid works because liquids are not appreciably compressible. Braking applications produce a lot of heat so brake fluid must have a high boiling point to remain effective and must also not freeze under normal temperatures. These requirements eliminate most water-based solutions. Although almost all road-going vehicles have only two brake pads per caliper, racing calipers utilize up to six pads, with varying frictional properties in a staggered pattern for optimum performance.