Security Boss Kennel Door Replacement RailsDescription Security Boss 16" Tunnel Extension The Security Boss Guillotine Kennel Door Rails can be purchased as a separate item for customers that are looking to replace or upgrade their existing kennel dog doors. These rails allow for a sliding door that is 1 4" or 1 2" in thickness with their dual channel design. Rails are 69" tall. Specs 69" Tall Accept kennel doors 1 4" 1 2" thick Heaviest gauge thickness of any guillotine kennel door rail on