SureFlap Tunnel Extender for Microchip Cat Flap & DualScan

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  • Cat flap wall tunnel extension for the SureFlap Microchip & Dual Scan Cat Flap.
  • Stack as many liners as needed, each liner adds 2" to the framing range of the door.
  • Sureflap tunnel extension comes in brown or white to match your door.
  • Measure your total wall thickness and overall length of tunnel prior to purchasing.

The SureFlap Microchip Pet Door Tunnel Extenders are designed for the SureFlap Microchip Cat Flap and DualScan Cat Flap models. Each cat flap extension adds 2" to the original self-framing depth of the cat door (2 3/4"), ensuring a secure fit through the installation area. Prior to purchasing, make sure to properly measure the wall thickness to make certain that you will receive the appropriate amount of cat flap extenders and that the tunnel extender fits

Size Chart

Flap SizeFlap DimensionRough Cut OutOutside
Cat Flap5 3/4" w x 4 3/4" h6 1/4" w x 6 1/2" h8 1/4" x 8 1/4"

Additional Information


SureFlap MicroChip Cat Flap

Installation Instructions

Step 1: Make a line on the wall for the cut-out that is 6 11⁄16” wide by 6 11⁄16” high.

Please Note: In order for your pet to be able to fit through comfortably, the bottom of the cut-out should be no more than 3” -4” from the floor.

Step 2: Prior to cutting, double check that there is no electrical, framing, pipes, etc. in the location you plan to install the pet door.

Step 3: Using the appropriate tools for the job (this depends on the material you are cutting through and if you are unsure then consult a licensed contractor), cut along the line that you’ve drawn.

Please Note: The manufacturer states that you can make a very slight gradual slope towards the outside to insure when installed any water gathering in the tunnel with drain out.

Step 4: Take the tunnel extenders and apply super glue to the corner tabs and fit them all together. Once the glue dries, use weatherproof tape around the outside of the tunnels.

Please Note: Do not glue the tunnels to the pet door.

Step 5: Take one side of the mounting adapter and drill the 4 holes in it using a 0.15” drill bit. The holes will be what holds the flaps to the inside of the house. You can put the screws on the two sides, the top, and the bottom.

Step 6: Using the washer screw and shortest screws provided with the door, mount the pet door to the adapter.

Step 7: Fit the cat door and adapter through the cut-out.

Step 8: Take a pen and mark the four holes you made through the adapter. You should also remove a little material from the wall in order to recess the screw and washer to make it flush to the wall. Remove the door and adapter.

Step 9: Drill the holes in your wall with the appropriate drill bit for the material of your wall and the screw you chose.

Step 10: Tape the tunnels to your cat door using the same weatherproof tape as in step 4.

Step 11: Mount the cat door with the tunnels and adapter in the wall from the inside. Screw it into place through the holes in the adapter.

Step 12: You will see the tunnel sticking out of the wall from the outside, so take the outside frame and second adapter and fit it over the tunnels and against the external wall.

Step 13: Make a mark for the screw holes. Remove the frame and adapter and drill out the holes.

Step 14: Fit the outside mounting adapter over the tunnel, followed by the outside frame over the tunnel against the adapter. Screw them to the wall.

Step 15: Use some small screws to drill through the top of the tunnel sections and into the frame to secure it.

Step 16: Use a silicone sealant to seal anything that has the potential to get water in it that would leak into the wall.


How thick is the liner with a code of 04sf01?

Each liner adds 2 inches to the tunnel length. The original door is 2 3/4" thick.

I have a cat door with tunnel in brown. Do I need the extender?

The extender is optional, it adds additional width to the cat flap tunnel, so that you can install your cat flap into thicker doors.


SureFlap™ Cat Door Guarantee

Guarantee: SureFlap™ microchip cat flaps carry a 3-year guarantee from the date of purchase, subject to proof of purchase date. The guarantee is restricted to any fault caused by defective materials, components or manufacture. This guarantee does not apply to products whose defect has been caused by normal wear and tear, misuse, neglect or intentional damage.

In the event of a part failure due to faulty parts or workmanship, the part will be replaced free of charge during the guarantee period only. At the manufacturer's discretion, a replacement product may be provided free of charge in the case of a more serious malfunction. Your statutory rights are not affected.

Disclaimer: The SureFlap™ microchip cat flap incorporates selective entry features which have been designed to minimize the risk of unwanted animals entering your home. However, it is not possible to fully guarantee the exclusion of all other animals in all circumstances.

In the rare event of an unwanted animal gaining access to your home, SureFlap cannot accept liability for any damage or inconvenience which may be incurred.

Warning: The motorized catch and manual lock are provided exclusively to prevent the entry of unwanted animals and is not a security device. SureFlap Ltd cannot accept liability for unintended use and the owner of the product accepts full responsibility for supervising the access in and out of the home that it provides.

In households with children, it is essential to include the cat flap in child-proofing considerations. Misuse of the cat flap by a child may result in the child coming into contact with potential dangers. For this reason, young children should be monitored at all times when in the immediate vicinity of the cat flap.

Caution: Prior to installation, it is the responsibility of the user to consult all building codes which may influence the fitting of the cat flap and assess the suitability of a given installation. The user must also consider potential hazards present inside or outside the cat flap as well as the impact that subsequent modifications to your property may have on the existence and use of your cat flap. It is recommended that these assessments are conducted in consultation with a construction professional.

Do not install SureFlap™ in a fire door as it will render the fire door unfit for purpose.

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