Double channel stair nosings profiles can be of the retrofit type, or the type that butts up to carpet or tile.They are suitable for stairs and steps with a wider tread(usually over 300mm),especially if they are subjected to heavy foot traffic.Originally developed for mass transit stairways usually found in railway stations,supermarkets,hotels,hospitals and other commercial establishment,the walking surface consists of an anti-slip PVC insert bonded to a heavy duty extruded aluminum base,or self adhesive diamondtred inlay adhered onto aluminium channel.