This eliminates the stress and frustration caused by the unwelcome intrusion of neighbouring cats, providing a safe and secure environment for your cat. The Cat Mate Microchip Cat Flap is very easy to program and up to 30 cats can be registered. For cats without an implanted microchip, a unique Cat Mate I.D. Disc can be attached to your cat’s collar (available separately). The easy to use, rotary 4-Way lock gives complete control over your cat’s access to and from the house. The streamlined design of the Cat Mate Microchip Cat Flap maximises entrance opening space - providing easy, stress-free access for your cat. The large 144mm(W) x 150mm(H) opening is fitted with a transparent flap which is preferred by most cats and is made from super tough polymer (cut out size 173mm x 198mm). The brush sealed flap with magnetic closure ensures a draftproof and weatherproof seal. The Cat Mate Microchip Cat Flap is self lining to 85mm thick - ideal for fitting to all doors, including metal. The cat flap can also be easily fitted to walls or glass panels with an adapter kit (available separately). For wall thickness over 85mm, a Cat Mate Elite Wall Liner will be required for each additional 50mm (available separately). The Cat Mate Microchip Cat Flap is battery powered and will give approximately 12 months operation from 4xAA batteries (not included). The LED indicator flashes with a short pulse every 30 seconds when the batteries are in need of replacement.