Aspen Pet Porter Traditional Kennel 36", 50 to 70 lbs: Assembles easily with metal nuts and bolts for a quick, no-hassle setup and a sturdy construction Ventilation openings in the plastic dog carrier provide improved visibility and ample fresh air for pets Lightweight, plastic design allows for easy and secure travel and transport Heavy-duty plastic shell and metal screws keep the Aspen pet carrier stronger for longer Aspen Pet Porter Traditional Kennel 36", 50 to 70 lbs: Assembles easily with metal nuts and bolts for a quick, no-hassle setup and a sturdy construction Ventilation openings in the plastic dog carrier provide improved visibility and ample fresh air for pets Lightweight, plastic design allows for easy and secure travel and transport Heavy-duty plastic shell and metal screws keep the Aspen pet carrier stronger for longer Airline Compliant - Meets most airline cargo specifications for easy and safe travel, but pet owners should always check with individual airlines.