Isn't it time you installed a Door Viewer (peephole) in your Front Entry Door so that when the Knock Knock happens a quick look the "CYCLOPS" will tell you if you should actually open the door. The cost of this security is minimal when compared to the cost of the family or home!
Door Viewers by "CYCLOPS" are wide angle peepholes made with (4) precision ground glasses affording the home owner a very clear and unobstructed full view outside their Front Entry Door. You can literally see the ceiling, walls and floor all at the same time.... there will be NO hiding!
Having the most expensive security system is of no use if you open the door to the wrong person!!! When you look thru the "CYCLOPS" you will know immediately if it's the Mafia, IRS, Pizza Delivery Guy or your sister Linda. Required: 9/16 Drill Bit
