Some VERY important things to tell all of you. Do NOT use "two-way deadbolts" on any of your doors or have something that you cannot get out of without using a key as a means of opening it to exit your home. My husband is a coroner, has been for 40 years. He has pulled so many dead people out of house fires who had those things including locking burglar bars that it would scare you senseless. MANY of them found on the floor with the key in their hands, or the key still in the door, but they were unable to use it. In a house fire "seconds" lost trying to fumble for or with a key means the difference between life or death. EVEN if the key is "handy" you may not have the preservation of mind to use it due to the overwhelming effects of the smoke.............it causes GREAT disorientation. When plastic burns it creates cyanide gases and other items in the house also add contaminates to the smoke as well. Your oxygen level drops as does your ability to reason and function from inhaling the smoke We ALL have plastics of some kind in our home. I have never known of anyone who can tolerate smoke from a bar-b-que grill, a wood fire, etc........but you take the black and very sooty smoke from a housefire and it is multiplied several hundred times over to what a simple wood or grill fire smoke does to your system. Firemen, coroners, and other officials who have been witness to these events NEVER use "two-way" deadbolts, or ANYTHING that would keep them from exiting the house in case of fire or home invasion. A two-way deadbolt is one that has to be opened with a key from inside the house. Same with burglar bars, windows, etc. You can use them regularly without problem, but in the confusion and excitement (not to mention terror) and the effects of smoke and or possible threat of physical bodily harm due to someone trying to enter another location of your house, you will not be able to respond effectively and it can cost you your life. We have storm windows and security doors that use plexiglass, it is practically unbreakable, it will crack, but not break. Those doors are also one-way deadbolts. The security doors are patterned metal, but are what is known as "full coverage" in that there is not space enough to get a hand through them and they have two locks on each door. Both of them one-way deadbolts, just turn the knob and they will easily open. Just last week my husband worked a housefire and the man was found at his window with the key to his burglar bars in his hand, the door exits were inaccessible due to the fire. So, folks, please pay attention to this one, everyone thinks they can respond in these situations, but housefire smoke, and/or some kind of home invasion are not "normal" happenings and everyone does panic in them, no matter how many times you practice exiting the house. A good example of that kind of "nervous apprehension" is where you were very nearly in an automobile accident, but managed to escape it. You are shaking, your adrenilin is up, your heart is racing, you are breathing heavy (in case of fire inhale more smoke if this happens). Calmness just does not occur in situations where your life is in danger. I just hope this helps someone. My husband changed out the locks on my grandmother's house the first time he saw them, from two-way, to the one-way deadbolts. She was unaware of the danger, but when he explained to her what usually happens in the case of having to use a key to exit anything in case of fire, etc. she was more than glad he took the time to do it. J Parker