my friend has viper glx's professionally installed at his house, and the slightest knock anywhere on the window frame triggers it. one might say this is oversensitive, but i do like this level of sensitivity.

Postman, window cleaner, lorries, fireworks, thunder etc. Setting them that high reduces the systems overall integrety.

IME people try and get away with one viper to cover the entire window (often fitted just above sill, or just under lintel). ok for small all in one contruction type windows but pointless on multipaned with several openers. Then have to leave on max.

and then theres impacts on U-PVC .................. why?

and then theres impacts on U-PVC .................. why?

Must admit I hate impact detectors on windows full stop.

They have their uses, vault walls etc but personally I would be reluctant to use on a window.

True, they dont work well on (esp cheap) upvc windows, but then they dont work hardly at all if you only put one in top/bottom corner of upvc window, hence post - too many specifiers think cause it says up to 9sqm thats all you need, 1 shock in the corner.

Well known national window fitter does wireless as above!

True, they dont work

all that needs saying IMO.

They do work, but careful design is needed, ie confirm groups on police response etc.

Audible only avoid front windows as well as people knock these sometimes if no-one answers.

correct placement for fixing type essential, but we do use sometimes on police response, vaults, skylight security grilles, walls, roofs etc.

Correct setup essential mind

They do work, but careful design is needed, ie confirm groups on police response etc.

Audible only avoid front windows as well as people knock these sometimes if no-one answers.

correct placement for fixing type essential, but we do use sometimes on police response, vaults, skylight security grilles, walls, roofs etc.

Correct setup essential mind

I have mine on hardwood framed glass double doors, mounted at direct centre between the doors, midpoint on the frame.