NOTE! ! ! Please ensure to measure your track height, sliding door width, and pet width before making a purchase. Dog Door For Large Dog: The FUELIO pet door for sliding glass doors has an overall width of 14.5 inches. Please ensure there is enough space left for people walk through. The opening flap is 11.4 inches wide, so measure your pet's widest point before purchasing. Adjustable Frame Height: Thanks to its spring-loaded design, the door height can be adjusted between 78'-82", properly fitting your sliding glass doors in patios, villas, and apartments. If your cats or dogs are with shorter legs, please note that the threshold is 6.3 inches high.