A guide rail is a device or mechanism to direct products, vehicles or other objects through a channel, conveyor, roadway or rail system. Several types of guide rails exist and may be associated with: Factory or production line conveyors. ... Roadways and bridges (in this context sometimes called guardrails)The system is made of two firm pieces of foam on either side of the heel. On the inside of the heel, the foam reduces the rolling of the foot inward. On the outside of the heel, the foam is both firmer and higher, reducing the shifting of the heel in the outward direction.