We bought for all the glass doors and windows of the house, afraid to see our Loulou pass over land and 4 floors below ... These handles are perfect, no complaints about the security system. Once installed, just push the button to the handle is locked. To reopen it, nothing complicated! A key to hit and it's done! In addition, the handles have the same lock which is handy. A key placed high in the important pieces and remains safe from little hands. Since I saw that all openings are secured with these handles.