Sherpa Travel Forma Frame Crash Tested Pet Carrier is our safest carrier yet! Crash tested to help keep every passenger in the car safe while traveling. The medium carrier is part of our Guaranteed on Board program for airline travel. The extra large bag is designed for car, bus or rail travel. Strap the carrier into your car using the standard safety belt latch and car seat tether system in your car. Windows provide your pet ventilation and more enjoyable travel experience. Extra strong seat belt-style straps provide the ultimate in strength and security. Included is a luxurious quilted liner to keep your pet comfortable and cozy.