Home > Window Locks & Latches > Defender Security U 9819 Sliding Window Security Lock, Economy, Aluminum,(Pack of 4)

Defender Security U 9819 Sliding Window Security Lock

Sliding Window Security Lock

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BVR Rating 168 reviews
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About Defender Security U 9819 Sliding Window Security Lock

The secondary lock fits up to 1/8 In. Thick rails allow the window to lock in ventilating position. Finish by tightening thumbscrew with pliers to securely lock windows.

Analysis of 100+ reviews for Defender Security U 9819 Sliding Window Security Lock


BestViewsReviews analyzed 9,651 reviews for 50 products in the Window Locks & Latches category.


We analyzed a total of 168 reviews for this product out of which, 106 reviews were received in the last 6 months.


The analysis indicates that around 63% reviews were positive while around 34% of reviews had negative sentiment.

BestViewsReviews Ranking and Score for Defender Security U 9819 Sliding Window Security Lock


This product received a total score of 8.33 out of 10, based on review sentiments and user opinions related to 5 features:

  • Build quality
  • Value for money
  • Safety features
  • Installation
  • Overall satisfaction
  • What users have to say about Defender Security U 9819 Sliding Window Security Lock

    The locks on my windows are strong and do not break, so I highly recommend them for anyone who wants to feel more secure in their home or even if they like to leave their windows cracked for fresh air.

    If your frames are large, I recommend using 2 of these for a strong hold and flattening the pointed end of the screw for a better grip.

    I have been using a large spring clip to keep the window shut but these were mentioned on the Casita forum and they are much easier to put on and take off.

    These are a very strong security device that can be put on our windows and removed in an emergency. They beat the windows shut with real screws, and they are much more than the standard window locks that most teenagers know.

    They are smaller than the ones I have used before but they work just as well.



    How many are included in the package?


    There are 4 in a pack.


    Will this work on an old sliding window?


    I used it on all my sliding vinyl covered sliding glass windows and they are the same diameter.


    The picture measurement says 1/4", yet the description says 1/8".What size rail can this fit?


    The opening is 7/32" and a rail 1/8" to 3/16" can fit.


    Is this cast or extruded?


    There is no current data to give you on your question.


    Is it possible to use this for windows that slide up?


    If there is a lip on the window frame, the jaw can fit over it and the thumb turn can be tightened against it.

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