I bought this Combo set of two different Kwikset Smart locks because the keys disappeared to my 20-year-old set of the combo Kwikset Smart locks that came with my house 20 years ago and otherwise have worked fine. Each lock had been installed on a different door. This new Combo set is quite similar to the 20 year old set, but the old set appeared at least a grade or two up in finish and more robust/sturdier in feel and looks; however, the old holes in the doors necessary for each new lock to be installed were an identical fit. The new set's info says its safety grade is "ANSI/BHMA grade 3 certified" which is the lowest of their 3 grades. Theoretically #3 tests without failure for 200,000 rotations of the mechanism (the other two are #1 - 500,000 and #2 - 300,000 respectively.) I figured we'd open each of those doors at the most perhaps 1,200 times during the next 20 years, and further, I could get these new locks overnight from Amazon at a decent price. This Combo gets only three stars overall. Initially, referring to the lock you see on the Combo page with a knob and a key slot in the middle of it for the outside of the door, and for the inside of the door a similar knob but with a twist-bar in the middle that opens the lock with a twist, this was the setup that had several issues that cost it stars. Here's the narrative: 1. The Combo's new spring latch-mechanism that holds the door shut fit exactly in the place of the old one, but it stuck at the in-position when the latch was turned in or pushed in, which made it useless because it wouldn't spring back into the hole to hold the door shut. So I put the old latching mechanism back in which worked fine, and the new knob's turning mechanism fit through its middle hole exactly; thus, the old latch continues its duty. 2. Both the 20-year- old and the new knobs still had identical mechanisms for screwing the two long Phillips screws that connect the front knob to the back knob so they can ultimately be tightly pulled together on each side of the door. But here's the annoying and aggravating rub: Kwikset for decades now has been using a "notch system" on this particular knob/lock system for at least 20 years. I and other reviewers call it the notch system because of the way Kwikset engineered the coupling of the outside knob to the inside knob. It's a two-screw coupling system that you put together by first screwing the two long Phillips screws a little way into the inside of the front knob, leaving the screw heads sticking out for slightly more than an inch for the next part of this sadistic operation. Then you stick the front knob into the door hole and through the hole in the latching mechanism and hold the front knob there with one hand. Then you put the back knob into its hole using the other hand and here's the rub. On the back knob's outside plate there are two holes through which one sticks a screwdriver to screw the back and front knobs tightly together, and -- THEN it dawns on you when you look through those screwdriver holes in the back knob's outside plate, presuming you first have both the front and back knobs in the top-side-up position so you can see the Phillips screw heads through what are now morphed into four holes because you should be looking through BOTH the back knob's outside plate and also the matching holes in the inside holes in back plate fastened to the inside of the back knob. Stay with me. The Phillips screw heads are going to be under that inside plate, not on top of it. So now you're wondering how you can tighten the screws so it will draw the front and back knobs together, as you simultaneously mumble "What the ...." Then, presuming you haven't decided to send it back and instead decide to examine the whole thing for some unknown period of time trying to convince yourself that no one would create such a numb-skulled way to fasten the knobs together, you realize that right where the two inside holes are, there is a raised slip-in notch for each screw in that inside back plate. Their purpose is for you to slip those Phillips screw heads into and on top of those raised notches (before you start tightening those screws). You ultimately find the previous sentence is accomplished by a very firm coordinated turn, one knob in each hand, the front hand holding that front knob steady and the back hand doing the twisting of the back knob, but only after first turning the notches a little to the side so the screws can then slip into those raised notches when you execute that firm back-knob turn (which often produces a nice click when done successfully). But there's more before you execute the twist: To execute that twist successfully, BOTH screw heads need to be at EXACTLY the same screw-length sticking out of the front knob, that inch+ or so, and each screw head needs to be in EXACTLY the right place (and same pressure on each) in order for them to slip and click into their notches properly in tandem at EXACTLY the same time. I presume the average time for trial and error and then making that happen successfully is 20 to 30 minutes, because you may repeatedly get one notched and the other still going under the plate without notching, until you get it just right. In any event once you've accomplished that, you aren't finished. Then get a moderately long and thin Phillips screwdriver because you'll be tightening at an angle as the knob's circumference hampers your work. Further, you can only turn each screw alternately a little at a time so you don't pop one of the screws out of its notch because it got too catawampus relative to the other screw. If you do not routinely do these installations for a living, after you've hit the success point, and if it wasn't blind luck, you've mastered this and you'll probably be able to do it in your sleep. I speak of "blind luck" because there is very little space for you to look between the knob and the door to see what you're doing, but you can see a little and it helps. Patience is truly a virtue. 3. Now the next reason it gets only 3 stars. While tightening up the knobs against each other on the door, after I was about three-quarters or more finished, the twist bar in the middle of the inside knob simply popped out of the knob as I tightened, leaving a small hole where the plastic "straw" was that held it in there. Trying to push it back in didn't work, but the rest of everything else worked. Fortunately, that setup was installed on the door of a small storeroom of mine and it's highly unlikely anyone could lock themselves inside the room -- there's simply not enough room for both a person of any size and all the stuff that's jammed in there. Now, here are the things that helped it, taken as a Combo, achieve 3 stars. A. The other locking device in the Combo (for a side door of the garage), the new Kwikset deadbolt which uses only a key locking mechanism on the outside of the door (no knob) and a reasonably robust turn-bar on the inside of the door, also fits perfectly all the previous holes from its 20-year-old predecessor. In comparing this deadbolt's system to the first part of this Combo the "notch system," here's what underscores the nonsensical (perhaps idiotic) notch system used in the first (storeroom) system above for fastening the Phillips long-screws vs. the system used on the garage door deadbolt lock: The (garage) deadbolt locking mechanism also has (and had 20 years ago) two long Phillips screws to pull the front and back mechanism together; however, it is not the notch system, but a much simpler setup. The two long Phillips screws are simply put through the two screw holes in the inside turn-bar plate and then, still simply, screwed into the two "normal" screw receptacles in the sides of the deadbolt key mechanism which also pulls in the outside back plate when the screws are tightened. It takes less than a minute to screw in both screws, tightening both sides of the door. Some version of that is how every other type of Kwi
