Adjustable Interior Leash keeps your pet secure while leaving him plenty of room to lay down - the bag is a cozy bed to nap in too. Keep your pet safe on the road by securing the Zuca Pet Carrier with a standard car seatbelt, it winds around the frame, plain and simple. Dual wheel system climbs stairs and curbs with ease, for a comfortable ride for Pup. The Zuca Sport Frame's built-in seat accomodates up to 300 lbs. 9 color options have Flashing LED Wheels for better visibility at night - or choose the Black Frame with Non-Flashing Wheels.