Thank you for your interest in Gun Dog House Door® products. This page is our small 2-WAY dog door selection which accommodates dogs up to 20 pounds. Our chew-proof aluminum dog doors come in two designs, our spring hinge version designed after our world famous Heavy Duty Dog Door®, which is the more weather efficient version or our easy swing version, designed after our Easy Dog Door®, which is less weather efficient. Don't let the spring hinge design intimidate you or your pet, the force to move it is less than 1.5 lb., which is similar to opening a cabinet. Check out a YouTube video that a non-sponsored person posted demonstrating their chihuahua using the Heavy Duty Dog Door®. If this 3 lb. dog can use this door, your pet can use any of our spring hinge designed small dog doors, given the proper acclimation process.