SureFlap Dog & Cat Door Tunnel Extender, Brown

By SureFlap
Rated 3.25 out of 5 stars
$19.80Chewy Price
No Longer Available
This item may be discontinued. We're not sure when it will be available again.

About This Item


  • Designed to be used with the SureFlap Microchip Small Dog & Cat Door when it’s installed in a wall.
  • Allows you to build an easy-to-access tunnel for your pet to walk up to the door flap.
  • Fits snugly into the 2 ¾ tunnel of the pet door and each extender adds 2 inches to the overall tunnel length of the SureFlap Microchip Small Dog & Cat Door.
  • You can use multiple extenders to make a custom-length tunnel depending on your wall thickness.
  • Comes in two colors so you can choose the one that fits your home’s style.

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Compatible with: [SureFlap Microchip Small Dog & Cat Door] (

To install in glass or walls, use SureFlap Cat Door Mounting Adapter.

Questions & Answers

3 Customer Questions

Is this tunnel extender compatible with the SureFlap DualScan Cat Door?
Answer by ChewyJun 17, 2020
This extender is designed to be used with the SureFlap Microchip Small Dog & Cat Door when it is installed in a wall.

Is the purpose of the extender to permit the cat/dog door to be used in a door with panels?
Answer by ChewySep 29, 2019
This extender is designed to be used with the SureFlap Microchip Small Dog & Cat Door when it’s installed in a wall.

What are the dimensions of the tunnel extender?
Answer by ChewyFeb 09, 2021
Each tunnel extender is 2 inches thick. They are taped to the existing tunnel on the door (same size as the tunnel).

ReviewsWrite a Review

Rated 3.25 out of 5 stars
8 Ratings
Would recommend to a friend

8 Customer Reviews

Rated 1 out of 5 stars
By jascasa on Jan 14, 2023

Chewy needs to verify the part number

Be careful, there are multiple sizes of "small cat & dog door" so you need the correct extenders. Chewy needs to clarify the part number. For example, in my SureFlap Door instruction manual it says mine matches with extender number TUN101.

Rated 5 out of 5 stars
By Domo on Nov 1, 2021

Measure first...

Would have been great if I had measured first... I ordered one extension, turns out I needed two for a wall install. Otherwise the tunnel extension came fast and attaches to the petdoor like it should. Now I'm waiting for a second one to ship out so I can finish my install.

Rated 4 out of 5 stars
By Jack on Mar 17, 2021

Definately Tape Together

If you need these to extend the tunnel through a wall, like I did, make sure to tape them on the outside like the instructions say. The plastic is fairly thin and gaps will appear at the joints as it flexes. I also made sure the bottom was supported by putting wood shims under it. I didn't want the floor to sag when the cat moved through it. Suggestion for filling the gap between these extensions and the outside trim piece: Use foam tape applied either on the outside of the extender (it it is accessible) or in the inside of the trim piece . Don't get me wrong, I like the product. The pieces fit together nicely and it was the perfect way to get the door installed in our wall.

Rated 1 out of 5 stars
By Phil on Jun 6, 2021

Extender too large

This extender does not fit the small cat flap, it’s far too large the product description is wrong

Rated 5 out of 5 stars
By Cris on Jun 12, 2020

Great product!

It is a great product, works perfectly for my dogs that are so happy now!

Rated 1 out of 5 stars
By Sheebaah on Mar 27, 2019

why not have tunnel extenders at various increments to suit USA users

even though this is a UK designed item, manufacturer is making a bundle of $$ in the USA, so why not accommodate North American building standard residential construction instead of tunnels for brick and mortar thick walls from the UK and make various tunnel extenders at incremental sizes other than only 2" increments, like say 1.0",1.5", 2.5" 3.0" - or are the extenders suppose to stick out that much (over an 1.5") and if so the edges of the plastic extenders seem kind of too sharp edges that may hurt cats and dogs as they are going in and out of the tunnel...poor design!

Rated 5 out of 5 stars
By Brenda on Mar 21, 2019

This is saving my sleep!

I no longer get woken up by my dog 2-3 times per night to go outside! This is a life saver paired with the petsafe door. Hallelujah!

Rated 4 out of 5 stars
By Chewey on Aug 11, 2018

Great Door

I love the SureFlap Door. It has helped train our puppies to use the potty outside. The only reason I rated it a 4 was because there is some space between the frame and the door itself. I worry about the winter time and heat escaping and cold weather entering.