I am expecting twins and I was regularly trying from the 9th week, when I bought it, to hear them. I managed (with quite a bit of searching) at 10 weeks and 2 days. I am very satisfied, it is reassuring.

At the 14th week I couldn't hear anything, I will return again with a review at a later week

It's really stressful, however you can usually find the pulse with a bit of searching, but sometimes when we were slow to find the spot, we were dying from anxiety

From the 12th week, I could hear the baby's heartbeat; you have to place it exactly where the doctor does the ultrasound to find it easily. It was the best gadget during my pregnancy to help relieve my anxiety until my next appointment.

I bought it online from Thessaloniki.
I am 15 weeks pregnant and the baby's heartbeat can be heard clearly.
It is very affordable and does its job.
It shows the baby's heartbeat accurately and also captures mine in a different position.
It takes a little time to learn how to use it.

No relation to the video provided below. It MAY capture the baby's heartbeat, it may not. Definitely not very clear to hear.
I will upload a video soon so you can see what it's about.
However, for some new moms, it works reassuringly, even so.
In terms of build quality, it resembles a part from the game "Barbie Doctor" ... completely fake.
I would gladly try something else...

Update after use
As I mentioned, it works reassuringly. For me, it has become a kind of companion, and every now and then I use it to listen to my baby. Okay, obviously the sound quality is not the same as that of the doctor's office, but I think the purchase was worth it in the end. I still use it even when we're just being a little silly, as a family, and it always makes us smile!
:)

Very good for its price! We used it with the special gel and with a little searching we always found the pulse!

It is a fairly honest product. The truth is that it is not very accurate in measuring heartbeats and someone may struggle until they find the baby's heartbeat. We used it in the 9th week of twin pregnancy and we could hear the heartbeats normally (after a little searching). Now that we know how to use the machine and roughly the position of the embryos, we find them almost immediately. Also, the purpose of buying it is to bring joy to the parents and not to add extra anxiety. Other than that, it is a very good product.

It's great, it works as it should! I followed the instructions according to the video below and found the pulse immediately (I was 17 weeks pregnant when I tried it).

https://youtu.be/tLx5UksAV1k

Excellent and for its money!!
VFM
It also has the batteries inside!!
You can find extra instructions on YouTube or generally on the internet - videos, that is!!
My wife is thrilled, I am happy and calm too!! ??

Thankful but doesn't work properly.... I am 12 weeks and it doesn't pick up anything.... I tried it on my own heart and it doesn't even pick that up.... I tried it with and without gel and no difference... Money wasted

Quite value for money. I read from the comments that gel was needed whenever I bought it, but it was not necessary. It works better when you are sitting rather than lying down, the heartbeat sounds more intense. I like that it also produces a graph at the end. I would recommend it especially to new mothers who are anxious and want to hear their baby's heartbeat.

I am exactly 11 weeks pregnant and I heard the baby's heartbeat very clearly ❤️️ I ordered the fetal Doppler along with an ultrasound gel. It cost 48€ in total. But it is understandable because it is very small.

Unfortunately, it does not work properly. While I can hear our heart if I try it, the baby (who is not a little one) cannot hear anything. We will definitely return it

Very good product. It needs Ultrasound Gel to function because that's exactly what it does. It detects the baby's heartbeats using Ultrasound and approximately measures the beats per minute, which is quite useful.

The doppler is excellent, we used it from the 10th week until my delivery at home. :)

Update:

No need for ultrasound gel as I see other reviews mention, it works just fine with regular lubricating gel from the supermarket.

Generally, you need to know the position of the embryo, and unfortunately, if there is enough abdominal fat, it is difficult to be accurate from an early week and show the embryonic heartbeat.

In no case is it worth the trouble for someone to buy it! There is no pulse sound, even though it shows pulses on the screen at any point of the body you touch it!!!!! Obviously, it doesn't work properly!! I do not recommend it to anyone, you will simply throw away your money! It is better to spend a little more to get a more reliable device.

Very good product and very easy to use!!
The only thing you need is ultrasound gel to isolate the sound and prevent scratching, and to locate where the baby is approximately! I am 5 months old, so it's not very difficult for me to understand where it is. In a smaller month, I don't know how easy it is to locate, I didn't have the machine.