Hardwired Smoke Alarm, 10 Years Photoelectric Sensor Smoke Alarm, Interconnect up to 12 pcs with 9V Back up Battery, Mute Function for Home School and Hotel

I purchased the 3 pack of these non-brand name smoke detectors for just over thirty dollars. The model number is GS528A. They are small and very easy to install. Each unit is 3-7/8" in diameter and 1-3/8" in height and very unobtrusive on the ceiling. The units only work with a 9V battery (you cannot hard wire them). A battery does come with each unit, but it is a "general duty" 9V battery, and not at alkaline battery, so the battery will probably discharge quicker and sooner than an alkaline. I noticed one reviewer state the alarm body would not connect with the back bracket on all six of his units. Unless the 9V battery is installed and connected correctly in the unit, the alarm body will not twist on and connect to the mounted bracket (a safety feature). The battery needs to be installed before final assembly! The unit has a red light ring in the center of the alarm body that blinks on/off every 32 seconds. In the center of this red light ring, is the test button. The instruction manual says to check the unit weekly. If the battery becomes low in charge, the unit will chirp and the red light will flash every 32 seconds. The units come with 2 screws and 2 plastic dry wall plugs to attach each unit. I used a 5/32" drill bit to punch through the dry wall and install the plugs. The instructions are very complete on where the unit should and should NOT be installed for proper installation. It is a photoelectric alarm and I placed one inside each of 3 bedrooms. The alarm is LOUD....per the instructions, ">85dB at 3 meters". The instructions say it must be located at least 3 feet from a forced air outlet (heat/AC) and/or at least 3 feet from a ceiling fan. The unit can be placed on a wall (within 12" of the ceiling) or preferably on the ceiling. Each unit has a 3 year warranty on it from date of purchase. If the unit fails, you "only" need to mail the unit to Siterwell Electronics Co. in Zhejiang Province, China, per the instructions! I'm pretty sure, if the unit fails within 3 years, I will purchase another unit made in the States rather than send the unit back to China......thus the reason for 4 stars! There is also a card inside the package stating that if there are any problems with the unit(s), please contact "Vodool" and provides you only with an email address, but no phone number or address. Since Amazon will not allow email links, I'm unable to provide you with the email address. Only time will tell if these units are quality or not.

I love this little set of smoke detectors! They are smaller than I had thought they would be, but they are just as loud as a full sized model. The batteries are included in the box and once installed the red light flashes every minute or so to let you know that the unit is ready. Pressing the test button produces a red flashing light and a very ear piercing sound. I feel confident that these would wake my family in the case of a fire.

THESE ARE GREAT FOR THE PRICE, EASY TO INSTALL AND LOOK GOOD. YOU REALLY GET WHAT YOU PAY FOR WITH THESE PLUS A LITTLE MORE. I INSTALLED THEM MYSELF AND TRUST ME I CANT INSTALL ANYTHING! IF YOU ARE A SINGLE MOM OR HAVE A LAZY HUBBY THESE ARE FOR YOU!!

Easy install, I did it myself. Came with a backup 9V battery.

It's a good thing my dad is a handy man and jack of all trades (master of tons!), else we'd still be sitting around the coffee table just staring at the computer screen and this little item, then eyeing the ceiling... Our new home only had one (ONE!!!!) smoke detector, and has never had more than that since it was built in '87. Crazy, right? Since we're on a budget, we're slowly adding to the collection one by one, and have been trying out a few different bands and styles. Why not, right? If we find one we love more than the others, we'll switch to that exclusively; as for now, we've got quite the conglomeration!It beeps! It's very loud... And it detects smoke pretty quickly! It will do the job if we get another one to put in the kitchen (for when the hubby cooks...), but this one has already been installed in the barren-of-detectors basement, and will hopefully never go off :D Fingers crossed!

Well made arrived on time , but lost a star because the mounting holes did not line up with electrical junction box. Had to drill new holes in base to mount. Other than that nice replacement alarm.

I like how easy the smoke detectors were to install. The test button displays a red flashing light with a loud beeping noise. I'm very happy with my purchase.

Shipped really fast, best price I could find for a 2 pack, and work great.I have had them I stalled for several months now and even after setting them off about once a week (I cook a lot with a grille pan inside) they still have full sound and no battery changes.Definitely recommend.