These worked perfect! I replaced our original builder interconnected 18 year old FireX 120-1182 Ionization (Flame) Fire Detectors with BRK/First Alert 7010B (Photoelectric Smoke) Detectors. The thought of rewiring each detector in the ceilings was more than unpleasant since I am still recovering from hip replacement surgery and teetering on a step ladder made me very uneasy. I saw these on Amazon, read numerous reviews (thank you everyone) and decided to try them. They worked great! After replacing all the units, I had the conversion time down to 5 minutes each (Hint:Using an inexpensive power screwdriver definitely helped working overhead!). First: I removed the 9V Eveready Heavy Duty Non-Alkaline batteries that came inside each detector and replaced them with a new 9V Alkaline battery (probably not necessary...just a personal thing), I then 'push tested' each before climbing the ladder to install the new wiring adaptor (why put up a detector that may be a factory dud?). After finishing all the replacements, just to make sure both the 'interconnectivity and the smoke detection alarm really worked in a real life situation', I lit a paper fire in a pail (in a safe non-flammable area), then put it out after it got going strong so it would smoke a lot, then held it about 12" below the detector. GREAT! All our new alarms went off at virtually the same time. So now I'm confident my family is safe in a real life situation and not just relying on a simple 'push' alarm test to hear a beep! Additional Note....I then also installed (6) BRK/First Alert Battery 'Family Gard' Model FG200 Ionization (Flame) Detectors as I felt we should have two different types of detection for safety. I bought three 2-Packs of these @ $10 ($5+- each). Well worth buying and in my own separate 'real life test' with real flames this time, these flame detector alarms worked, though only where a flame was present (they are not interconnected!). Because the Family Gard units are battery powered with no wiring required, I was able to install each in the same time of just a few minutes ~ with a power screwdriver :). Please think about adding additional safety for such a low cost. (Ionization + Photoelectric). Just my own opinion.... The installation of the new wiring adaptor was simple 'if you have strong' fingers.The new connector snaps onto the existing FireX 3-pin connector (at least on ours it had to) in order to secure itself and not pull loose. If you can't snap it together, you may be able to use a pair of pliers and slowly & carefully pinch the two connectors together working each side down a little at a time so you don't end up snapping or breaking the existing connector, until they snap together...If you break the existing connector or one of the three small pins, you will have to remove the existing connector and install the new hard-wired connector. The only other issue I ran into was pushing the new connector and additional wiring back up inside our already crowded ceiling box took a few different tries until a decent fit worked.Take your time here, I WOULD RECOMMEND DOING THIS BEFORE ATTACHING THE NEW DETECTOR TO THE NEW WIRE ADAPTORS. It's so much easier to deal with stubborn wiring in a crowded space without also having the new detector dangling below, hanging on the wires. If the new connector doesn't fit easily into the existing ceiling electrical box (it probably won't unless you're lucky), look at the wiring inside the ceiling box & try to find a relatively uncrowded area where the new connector will fit into, once you find or create that area, the new connector & short wiring should be able to be 'gently' pushed inside..don't break wiring connections!. Then go ahead and install the new connector wiring to the Detector. if the wires come out of the ceiling again while doing this, now, since you know how you're going to put everything back into the ceiling box (because of your trial run), just place it all back inside the ceiling exactly where you had it.... Having to buy 12 connectors at a time is quite an oversell, if I needed 8,9 or 10, then I would be fine with purchasing (2) 6-packs, but when a home has 6 or less, it really is an oversell. However having said that, I wouldn't hesitate to buy them again knowing now how simple it made the conversion from FireX to First Alert! NOTE: We are Amazon Prime members and I can say we absolutely did not receive any consideration, nor were we asked whatsoever for our comments here. Life is much too important for anyone to play games with. We purchased the wiring adapters from Amazon, but just to be fair to Amazon, we purchased the detectors mentioned above elsewhere. But again, to be fair, if we had not seen a super-sale within a couple of miles from home for these detectors, we would have gladly ordered and depended reliably on Amazon to deliver us these detectors within 2-days and to back us up if something was wrong!