As seen on the dragons den. 1 part of our two prong approach to securing your patio door. On its own it is an excellent security device to stop your patio door being jimmied or lifted out. When you combine it with our Patio Door Double Bolt Security Lock it makes your Patio door virtually burglarproof. Watch our video: http://www.youtube.com/watch?v=G79Lovi6FxE .