• Q. How long does it take to break in through caravan and motorhome windows?
  • A. Less than 5 seconds without additional security.

Anyone who has locked themselves out of their motorhome or caravan will have discovered how easy it is to prise open the plastic windows. This insecurity is caused by the flexibility of both the acrylic windows and the plastic latches. Chris's comments in the footer explain the caravan industry's reluctance to spend more to eliminate this vulnerability, meaning an aftermarket security device is your only choice.

You don't need to be a cat burglar to break in through a caravan window

Cat burglar breaking in through caravan window on a motorhome

The Polyplastic sliding window above has enhanced security from UK manufacturer Lock M Out, who produce a range of devices that secure or lock the latches of Polyplastic or Dometic/Seitz windows. 99% of motorhomes and caravans have windows from these two window manufacturers.

The first step to securing your caravan or campervan windows is finding the manufacturer's stamp

Polyplastic window stamp for Lock M Out securityDometic Seitz window stamp for Lock M Out Security


Polyplastic Window Security

Polyplastic windows have just one latch for outward opening windows and one for sliding windows as seen in the photos below.

PolyPlastic window latch with security device

You only need to buy enough push on devices for all of the bottom latches on your Polyplastic windows. See the detailed product images of the V3A Polyplastic window lock for more information.

Polyplastic Sliding Window Security

lock for caravan sliding window catch

The Lock M Out security device fits both left and right hand opening Polyplastic sliding windows. They can be fitted loose or screwed permanently, as photographed above. See detailed product images and information about the PSL1 Polyplastic sliding window lock.

Dometic/Seitz Window Security 

 Sietz caravan window Lock M Out latch

Caravans and motorhomes with push open Dometic/Seitz windows are secured in a second by simply bringing the device down onto the Seitz handle until the button pops through the hole. See detailed product images and information about the MR2 caravan window locking device. Right and left hand devices available.

Dometic/Seitz Sliding Window Security

Lock M Out manufacture two age-related Seitz sliding window locks. The width of the device is the same, but the depth to the retaining catch is further down on the old style window catch used before 2006.

Identify Seitz  caravan sliding windows before and after 2006

See detailed photos and information about the S4 Pre 2006 Seitz caravan window locking device.

See detailed photos and information about the S4 Post 2006 Seitz motorhome window locking device.

Chris Doree's Vicarious View:

I asked the managing director of Polyplastic why they do not produce more robust window catches. He explained, at length, that caravan and motorhome manufacturers will not pay for more secure latches. Having drawn a blank there I looked and found these practical and affordable add-on security catches being manufactured in the UK, which I have fitted on my own Wildax Europa van conversion and hope that you will too.

What Lock M Out catches fit my motorhome or caravan?

We have provided PDFs explaining what Lock M Out products fit which motorhome and caravan makes and models.

3 THOUGHTS ON “Motorhome and Caravan Window Security to Lock M Out”

by Gill Roberts

What good advice. We had a bar across our sliding window in our old van for ever, it was secure.
Now we have a new van, will look today to see what the windows are like, I know no sliding windows though.

by Andrew Naylor

I have a 2016 Rapido 9094df. All the windows are Dometic V-X/B yet there are three different types of catch. One type has a red button and a projection opposite the handle. Another has a black button and also a projection opposite the handle. There is no identification on these two but the third type has polyplastic stamped on it. Will the MR2 lock fit all three as they are all mounted on Dometic V-X/B windows?

by Peter Ingram

We had our camper van broken into in Spain and stuff stolen earlier this year. They prised open the lift up Seitz plastic windows and snapped the catches off. Lousy design!!
I will look at this idea for sure.