Cat Mate 303 Wall Liner Tunnel Extension – Fits 204, 209, 234 & 235

The Cat Mate 303 Wall Liner Tunnel Extension is a genuine Cat Mate accessory designed to extend compatible cat flaps through thick doors, brick walls and cavity walls.

Each tunnel section adds approximately 50mm (2 inches) of additional depth. Multiple sections can be joined together, allowing you to build the tunnel to suit the thickness of your particular wall.

This provides a much neater installation than leaving the inside of the wall opening exposed and creates a smooth, easy-to-clean passage for your cat.

Fits Cat Mate 204, 209, 234 & 235 Cat Flaps

The Cat Mate 303 Wall Liner is designed for use with compatible:

• Cat Mate 204
• Cat Mate 209
• Cat Mate 234
• Cat Mate 235

If you're unsure which Cat Mate model you have, check the model number on your existing cat flap before ordering.

Ideal for Installing a Cat Flap Through a Wall

A standard cat flap is normally designed around installation into a door or relatively thin panel. When installing through a wall, the distance between the inside and outside frames can be considerably greater.

The Cat Mate 303 tunnel extensions bridge this space and line the opening through the wall, creating a cleaner and more professional finished installation.

They are particularly useful for:

• Brick walls
• Block walls
• Cavity walls
• Thick timber doors
• Deep panels
• Other suitable thick installations

Each Tunnel Extension Adds 50mm

Each Cat Mate 303 section provides approximately 50mm (2") of additional tunnel depth.

If one section isn't enough, simply use additional tunnel liners to increase the overall depth. The modular design allows several sections to be connected together for deeper installations.

How Many Cat Mate 303 Tunnel Extensions Do I Need?

The number required depends on the total thickness of your wall and the depth already provided by your particular Cat Mate cat flap.

Please use this table as a guide only. Measure your wall and take into account the tunnel already incorporated into your particular cat flap before ordering.

Some trimming may also be required to achieve a neat finished installation.

Join Multiple Tunnel Sections Together

The Cat Mate wall liners are designed so that multiple sections can be used together. This makes them particularly useful for traditional UK brick and cavity walls where a single extension may not provide sufficient depth.

For example, if your installation requires approximately 150mm of additional tunnel depth, three 50mm sections can be used.

A Cleaner, Safer Wall Opening

Using proper tunnel liners means your cat isn't walking directly through exposed brick, blockwork, insulation or the internal surfaces of the wall.

The smooth plastic tunnel creates a much neater passage and is considerably easier to wipe clean if muddy paws leave marks inside the tunnel.

White Paintable Finish

The tunnel is supplied in white plastic, providing a clean finish that works particularly well with white Cat Mate cat flaps.

The surface can also be painted if you want the visible section of the tunnel to blend more closely with your wall, décor or installation.

Important – Position of the Locking Controls

There is an important consideration when installing some of these older Cat Mate models through a deep wall.

Depending on the model and installation, the manual locking controls can end up positioned at the far end of the extended tunnel. The deeper the wall and the more tunnel extensions you use, the less convenient the controls can become to reach.

The product image shows this type of installation using multiple tunnel sections.

If you normally leave your cat flap unlocked this may not be a major concern. However, if you regularly change the locking position to control when your cat can enter or leave, it is worth considering before choosing your cat flap.

Installing a New Cat Flap Through a Wall?

If you're purchasing a new cat flap specifically for a wall installation, rather than extending an existing 204, 209, 234 or 235, you may also want to consider the newer Cat Mate 358 Rotary 4-Way Locking Cat Flap.

Its rotary locking arrangement can provide more convenient control for installations where easy access to the locking mechanism is important.

Key Features

• Genuine Cat Mate 303 Wall Liner
• Designed for compatible Cat Mate cat flaps
• Fits Cat Mate 204
• Fits Cat Mate 209
• Fits Cat Mate 234
• Fits Cat Mate 235
• Adds approximately 50mm (2") of tunnel depth
• Ideal for cat flap wall installations
• Suitable for thick doors and panels
• Multiple sections can be used together
• Creates a smooth lined passage through the wall
• Easy-to-clean plastic construction
• White finish
• Can be painted if required

Product Specifications

• Product: Cat Mate Wall Liner / Tunnel Extension
• Model: 303
• Extension Depth: Approximately 50mm (2") per section
• Colour: White
• Material: Durable plastic
• Quantity: 1 × Tunnel Extension

What's Included?

• 1 × Cat Mate 303 Wall Liner Tunnel Extension

Please note: The cat flap itself is not included. This listing is for one tunnel extension section.

Frequently Asked Questions

How much depth does one Cat Mate 303 tunnel add?

Each section adds approximately 50mm (2 inches) of additional tunnel depth.

Can I join several tunnel extensions together?

Yes. Multiple Cat Mate 303 wall liners can be connected together to accommodate deeper walls.

Can I use these for a brick wall?

Yes. Wall installations are one of the main reasons for using tunnel extensions. They provide a neat internal lining between the inside and outside sections of the cat flap.

Will this fit the Cat Mate 234?

Yes. The Cat Mate 303 tunnel extension is compatible with the Cat Mate 234.

Will it fit the Cat Mate 235?

Yes. It is also compatible with the Cat Mate 235.

Can the tunnel be cut or trimmed?

Some trimming may be required depending on the exact depth of the installation. Measure carefully before making any cuts.

Can I paint the tunnel?

Yes. The white plastic can be painted if required to help the installation blend with the surrounding décor. Always use a paint suitable for the plastic surface.

How do I know how many extensions I need?

Measure the total thickness of your wall and compare this with the tunnel depth already provided by your cat flap. Each additional Cat Mate 303 section contributes approximately 50mm.

I'm not sure which tunnel or cat flap I need. Can you help?

Yes. If you're installing a cat flap through a wall or trying to extend an existing Cat Mate model, send CatFlaps.co.uk a photograph of the cat flap together with the approximate wall thickness. We'll be happy to help work out which parts you need.

Cat Flap Specialists – Here to Help

CatFlaps.co.uk has been supplying cat flaps, dog doors and replacement accessories since 2001, backed by more than 30 years of experience in the window and door industry.

We've supplied hundreds of thousands of pet doors and accessories across the UK. Wall installations can sometimes be more complicated than fitting a cat flap into a standard door, so if you're unsure about the tunnel extensions required, please contact us before ordering – we're happy to help.