several years ago my mother had k designers put up siding, windows and doors. two nights ago a thief tried REALLY HARD to get in through the glass and vinyl french doors in the back of the house. they really flexed and bowed but did not break or give. he finally gave up on them and kicked in the front door. i got it all on camera. VERY IMPRESSIVE!!! i am having them come out and replace them now. read full review »