BLACK+DECKERUniversal Security Instruments USI-1204 University Security Instruments Electric 1204 Hardwired Ionization Smoke & Fire Alarm | 120-Volt Fast Responding Alarm - Comes with Backup Battery

If you have an installed USI-1204, you can just replace the screw on bottom without having to change the base including rewiring. Mine was installed in 2004 (need to replace every 10 years) and it worked great for me. Very easy to just plug into already existing base and screw on the new bottom.However, suggest you search for best price. Amazon market merchant 7Day sold for $53 and now dropped it to$43 - this is a very high price. Amazon Prime at $30 per. USI Electric (from their online store) for $18 per.Price was important for me as I had to replace 9 units in my home.

While we have a full security system in our home, we also had two of these units installed when we completed a new addition. Believe it or not, they each lasted about eleven years before failing with a loud and constant wailing--at 3:00am on consecutive nights. Being somewhat confused and tired on the night when the first one went off, we thought that they were wired into our primary alarm system. When we tried to disable them on the alarm panel, it set off our main system resulting in calls from the security company monitors. Unfortunately we forgot that they were independent of the primary system and our efforts to disable them actually caused us to set off the main panel. OOPS! I finally figured out how to disable them and pulled the front panel off and disconnected the battery. That worked so well the first night that I was ready for the second one to go off on the next night. I wish that I had simply disconnected the second one so that we didn't have to deal with another alarm that second night. Live and learn. So if one of these does fail in the middle of the night, just pull off the front cover by twisting it to the left and then pull apart the plastic battery connector.Then order two of these USI 1204's. These are the perfect replacement. You don't have to mount the new base that comes with it, just remove the top part with the battery in it, pull out the plastic sleeve to activate the battery, and twist the new cover into the old mount. A green light should come on and you're "good to go". Good price, fast delivery, and easy to install.

The house was built 13 years ago, and these were installed at construction. The newer models have a different base, and I've been happy with the performance of this version since the house was built, so as the old ones needed replacing, I opted for exact replacements rather than a full upgrade to the new bases. These are hard to find nowadays and the ones here are Amazon are not old stock, but rather newly manufactured ones, which means they work perfectly. Super easy to replace on the old sockets, and I've not had a bad one in all the ones I've replaced. Excellent purchase!

Fit rite on my 20 year old USI 1204 bases so it was just plug & play. Came with new base as well but just more work to use them. Old base and new sensor were slightly different shades of off white. not too noticeable from a few feet away. Nice and loud. AC & 9Volt B/U. Less than 10 min, to change all 5. Just twist left drop unplug, ( no lock just pull straight back) only goes one way color will line up plug new one in align,push turn right, see green light ,push button test loud beeps ( Ear protection advised ) done. repeat on next one!! you can buy cheaper ones but way more work! ordered Sunday afternoon came in and installed Monday afternoon. I ordered 9v battery's but it comes with a new one installed just pull the tab. only bad thing is it was stamped made in 2020 so already 2 years old? I would buy again.

After watched a Today Show episode about testing and replacing smoke alarms. We took a look at all the units in our house. They are all hardwired and were installed by the previous owner, who built the house. Following the test prescribed by the episode, a few didn't work, despite having a gree light on. Then we took those down and found the use expiration was 2012, five years ago!! What's great about this unit is that it is a Plug N Play replacement for our hardwired units... all we had to do was unplug the old unit and plug this one it... LOVE IT!!!

Replaces aging (15+ yrs) models that are discontinued. Used existing ceiling mounts. Popped right onto mounts after new "Brand Label" batteriesinstalled. Didn't trust the gimme "GP" brand that they came with. Had 4 of my 7 units ripped out of ceiling due to constant beeping. Now all 7 unitsback in and WHOLE house protected!!!

I replaced my old device and this one was the same color and size. I was happy that it was the exact replacement, didn't have to paint anything. I'm super happy with it. It was a less than 3 minutes replacement. Perfect for what I needed! I highly recommend you match the old product number to make sure you are getting the exact replacement item. Delivery was fast and the product was intact as promised. I highly recommend.

I replaced the same smoke detectors to avoid having to install a new base.I ordered and received 5. All 5 have a 'replace by' date of 2028 - only 9 years in the future instead of the 10 years the manufacturer states.Once Amazon was aware of the issue they made good in no time.All are working fine and it was a 30 second job for each (plus setting up the ladder) to have them installed. Great replacement product!