These work great and we use them a lot. when you first get them, make sure you have the batteries in right. The thicker side of the flat batteries goes in so you can still see it once it's in. Just push it in till it fits. There is no click. Then, when you use the control pad, hold the key down for at least 5 seconds. I thought it was broken for a few hours because I didn't realize I couldn't just click the buttons. That said, SOOO glad I bought this. It's a great product at a great price. There is a flash light on the control and each pad has a small red light and makes a noise.

Original Product Broke withing two months but Company sent a new one at no cost and has been working great.

Works great, but goes through batteries quickly. I like it though.

Expect to replace the batteries shorty after receiving it, the batteries died with very light usage within a few weeks in every single unit.
UPDATE: after posting the review above and originally only rating the device with 2 stars, I received an email that I would be given a full refund - without having asked for one, never, ever have had that happen before -  excellent customer service so I updating my rating.

Not all worked when I tried them so I gave it a 2* (they sent out a new kit with out me asking or returning the first one this new box works

It's perfect.  For the price it's a GREAT DEAL!! It comes with batteries for each of the color coded finders.  You will need to buy 2 AAA for the home unit.  Also I bought a magnet for the home unit to stick on my fridge.  Because keeping it on the dock Im sure it will get lost too.  Lol. Definitely a great buy!

All four key finders worked initially, one stopped working about one month after arrival. Overall, the ones that still work, work appropriately and reliably. The range covers my entire house and yard. Even though one does not work, they still seem worth the money, given the low cost, and I would recommend them to friends and family.

Do you have kids?  We have three of them. By the time I get home from a long day at work, sometimes I just need a little Netflix or Amazon Prime.

Before I got these, there was this hellish period of "You've got to be kidding me?  What do you mean you don't remember where you put it?!?!"  Sure, we had a designated basket where the remotes should go, but they'd be under the couch, under a blanket, in the next room, etc.

Now, all I do is click a button on the base remote and the fob chimes away and we have fun finding the cussed little devices. Sure, they still end up in every conceivable unusual spot, but now we can find them.

It works through furniture, at least 20-30 feet away. If there are walls involved, no biggie, I just walk around with the remote clicker and push a few times. Never failed us in about two months of use. If you'd like to use it for keys, I think it would work equally as well.

Each fob chime it a simple series of beeps, but each has a different note or tone. So if you're searching for multiple items at a time, you'll just hear different notes.

My only complaint is the form factor doesn't work aesthetically for our current use, but we don't care. Now we can find our remotes in seconds. I'd give it 4-4.5 stars for that, but the positive impact it's had on this small sliver of our lives is fantastic. First world problem, but now it's solved.

I highly recommend this product!

I am FOREVER losing things... So far I am only using 1 of the 4 locators - on my Kindle... My husband put a rubber band through the transponder, then attached it to my Kindle case. It is BY FAR worth the price. I have about 12 other things (At least) I could use these for. Not sure if I  buy multiples if it will work. But I have to say, I am SOOOOOOOO Happy to be able to find my Kindle when I misplace it.

Stopped working after six months.  It was not the AAA batteries in the home unit.  It might have been the disk batteries in the units on the keys, but it did not seem worth replacing them to find out.  I'll just try to be careful with my keys.

Added later.  A day after I posted this review, I got an apologetic note from the vendor offering a full refund.  I did not expect that!  The refund came in the form of an Amazon gift credit, rather than a refund to my credit card so I did not spot it for a day or so.  But I have to say this is a very responsible seller.  I'm going to raise my rating from one star to four.