SureFlap Microchip Cat Flap

A product review by Bobulous

About the SureFlap Microchip Cat Flap

The SureFlap Microchip Cat Flap is a cat flap which permits entry only to selected cats who are identified by RFID microchips. Such a flap is necessary where unwanted neighbourhood cats enter your home through an existing cat flap.

Before you purchase a microchip cat flap, you need to check that it is able to read an existing RFID microchip implanted in your cat, or pay a vet to implant a compatible microchip. The SureFlap website has a compatibility checker, and it also offers a download of the instruction manual.

Installing the SureFlap Microchip Cat Flap

photo: A view of the SureFlap Microchip Cat Flap, looking straight through it at the garden fence.
The SureFlap Microchip Cat Flap installed in a PVC door.

The SureFlap Microchip Cat Flap provides instructions for installation into PVC, wooden, and metal doors, and into plasterboard and brick walls. It also provides instructions for installation in single-glazed glass doors and windows, but cautions that a qualified glazier should be hired to do the glass cutting.

I installed a SureFlap Microchip Cat Flap into a PVC door, to replace an existing cat flap. Conveniently, the existing tunnel hole for the old cat flap was just the right size to fit the tunnel of the SureFlap Microchip Cat Flap, so I only had to drill two new holes for the bolts which hold the new flap in place. Drilling through a PVC door is harder than I imagined, as the thin-looking door panel is actually two skins of PVC wrapped around a thick layer of insulating material which the drill bit does not like much. But it was still relatively short work to convert the existing hole for use by this new flap.

Before you buy a SureFlap Microchip Cat Flap, make sure to read the product instruction manual and think about the installation process to work out whether or not you are prepared to make the adjustments necessary to install the new flap.

If possible, consider positioning the new flap so that it looks up the length of your garden. We installed ours in a door which looks straight at the nearby fence, so the cats can't scan for trouble before they head outside, and this causes them to fuss and dally before they exit.

Using the SureFlap Microchip Cat Flap


The SureFlap Microchip Cat Flap uses four AA batteries, and these slot into the top of the indoor portion of the flap. The estimated battery life is six months, but even with two cats we got closer to nine months' use from one set of alkaline batteries. The instructions advise that rechargeable batteries can be used instead of alkaline, but say that rechargeables tend to produce lower voltage and will need to be recharged every few months.

Note that the battery compartment is on top of the flap, and it doesn't have any weather sealing. So if you install it in a door which opens outwards, you'll need to make sure to close the door if it starts raining, otherwise the battery compartment might fill with water.

Learn mode

With the batteries in, it's time to train the SureFlap Microchip Cat Flap to recognise friend from enemy by telling it which microchip RFIDs belong to your cat or cats. The flap can allegedly remember up to thirty-two different friendly RFIDs, but we only needed it to remember two.

To add a new RFID to the flap memory, you simply open the battery compartment and press the "memory" button for one second, which unlocks the flap and causes the LED to blink. Then the next cat (with a compatible RFID microchip) which wanders through the flap is remembered as friendly. From then on, that cat will cause the flap to unlock each time it sticks its head into the tunnel from outside, so that it can enter your home.

Because both of the cats in my home are slow-witted, I decided to cut a hole into a large cardboard box, fit the SureFlap Microchip Cat Flap into the side of the box, and then put tasty treats into the box to lure the cats to stick their heads into the new flap. This not only made it easy to add both cats to the flap memory without having a PVC door in the way, it also helped to get the cats used to the loud click the flap makes when the locking catch jumps out of the way to allow a friendly cat in. Both our cats jumped out of their skin the first few times, but soon became uninterested in the loud click once it was familiar.

Cat training

photo: A view from above while a large cat is halfway through exiting through the SureFlap Microchip Cat Flap.
A feline beast squeezes its bulk through the flap.

Once the flap was installed in the PVC door and both our cats were recognised as friendlies, the hardest part was encountered. As mentioned, our cats are about as slow-witted as cats get, and at first they could not work out how to get through the new flap. This was partly because there is a drop from our back door down to the garden surface, and a step between the two. The tunnel of the SureFlap Microchip Cat Flap sticks out much further than the old flap did, and this makes it harder for our cats to use the step.

In the end we held the flap open with duct tape so that the cats could first get used to the different profile of the new flap. Once they had the hang of that, they did eventually get the hang of triggering the unlocking mechanism and then pushing their way through the flap. This did take nearly a fortnight of human intervention, but smarter cats would probably take far less time to get the hang of it. If you have dopey cats, it might be wise to install this flap in the warmer months to avoid freezing yourself, your cats and your home during the adjustment period.

It's also worth mentioning that our cats just about fit through the flap as they're on the large side. The flap dimensions are 142mm by 137mm on the SureFlap Microchip Cat Flap. If you have excessively large or obese cats, or if you want a selective flap for a dog, there is also a SureFlap Microchip Pet Door which has a larger flap size of 178mm by 170mm, but I have no experience of the SureFlap Microchip Pet Door.


Since putting the flap in place and getting the cats up to speed, everything has gone very smoothly and alien cats are no longer able to get into the house. Because the automated locking mechanism always allows the flap to open outwards, I was worried that enemy cats would be able to claw the flap open from the outside. But the long tunnel on this flap seemingly stops that from being achieved, so the SureFlap Microchip Cat Flap has so far reigned undefeated. I was also worried that enemy cats would be able to jump in through the flap right behind our cats, but the locking catch jumps back into place very quickly once your cat is inside, so this has not been a problem so far.

The SureFlap Microchip Cat Flap also has a simple, plastic, manual locking dial which permits any of the following modes: "open both ways", "open out only", "open in only", and "no entry from either side". (Note that this does not alter the operation of the RFID automatic unlocking mechanism, but the RFID locking catch can be trapped open if you think of a reason to do this.) This manual locking dial should be very handy now and again (for instance, if it's time to take the cats to the vet, and you need to allow them to enter your home but not exit). However, there are no clear markings on the dial, so I find it very difficult to work out which position achieves each locking mode. It's also very stiff to turn, especially so once regular use has caused dirt and grit to get into it. So I just leave the manual dial in the "open both ways" setting. If SureFlap can improve the design of this manual locking dial for a future model, I'm sure it will be appreciated.

On the subject of security, make sure you never leave a key near the door or window in which the flap is installed. In the past a would-be burglar punched through our previous cat flap hoping to let himself in. (We know it was a male because he got caught burgling the house next door.) Keep door and window keys out of sight and out of reach of intruding arms, poles, fishing hooks, etc.

Evaluating the SureFlap Microchip Cat Flap

I'm a big fan of the SureFlap Microchip Cat Flap. The purchase price is affordable (though bear in mind you need to pay a vet to implant compatible RFID microchips in cats which don't already have them). The installation process is laid out clearly in the instruction manual, and the flap claims to support installation in a variety of types of wall and door. The battery life is acceptable, even with two cats using the flap frequently. The detection of friendly cats and the unlocking mechanism work without any problems, and even our dozy cats have got the hang of it.

Before installing a selective cat flap, alien cats would enter our home every night to eat our cats' food, and this left our own cats constantly alert and stressed. With this flap in place the intrusions have been stopped completely, and our cats are much calmer now that they can sleep in peace. I'm very pleased with the SureFlap Microchip Cat Flap, and recommend it for consideration by anyone subject to regular invasion by enemy cats.


It's a little over three years after the SureFlap Microchip Cat Flap was installed, and its latch mechanism has just failed. The SureFlap still detects our feline beasts but now merely makes a feeble pulsing noise of recognition; the latch no longer reacts. Initially the latch was stuck in the locked position, then fell into the unlocked position and has not moved again. Factory reset and fresh batteries have not fixed the problem, so I'm confident that this is mechanical failure. A replacement has been ordered, and I'll update this page if it gives any trouble.

The replacement proved to be exactly the same shape as the old unit, so it was easy to unscrew the old unit and remove it from the door, then place the new unit in the door and screw it firmly into place. It's been in use for a week now and has shown no sign of problems. Something worth mentioning is that the newer model has added helpful markings around the manual lock, which should make it a lot easier to work out which direction to turn it to stop your cats getting in or out through the flap.

As before, I decided to engage "learn mode" before the flap was installed in the door. I went and found each cat, placed the flap next to them, engaged "learn mode" and then placed a tasty treat on the shelf of the flap. This enticed each of them to stick their curious heads into the tunnel until the SureFlap recorded their microchip as friendly. Much easier than sitting by the door waiting for each cat to attempt to get in.

Same thing again: the latch mechanism broke, so that the SureFlap was permanently unlocked. At least this time it lasted over eight years. So a new replacement was ordered, and again it fit the old tunnel and screw-holes fine, making it easy to replace the old with the new. Only problem this time was trying to get both of the cats to stick their heads into it before installing it: the elder cat was having none of it, so I had to install it in the door and leave it in "learning mode" and wait for her to get to it in her own sweet time.

Ideally these things would easily last more than ten years, so that it wasn't necessary to buy three of them in the space of just over a decade.