Patent pending Length Extender cleverly adds more interior space for your pet when you want it * Four sided mesh windows with privacy shades provide added comfort and privacy * Three easy access entryways offer convenient top loading or walk-in-entrance * Airline approved for in-cabin use. Choose the right size for both your airline and your pet. * Small 17"L x 10"W x 8.5"H. Regular 18"L x 12"W x 10.5"H. Large 18.5"L x 12"W x 12"H.