Negatives:
The heart sounds are quite quiet to be heard at full volume.
Unfavorable Handling: The whole bottom of the device is always fully lubricated with ultrasound, it's a mess, always wipe the whole bottom of the device.
The headphones push very. (Unfortunately, my own In -Ear - handset does not work with it.)
The "smacking noise" from the drive around on their stomachs are totally uncomfortably loud, but if you turn up the volume quieter with the device, you can hardly hear the heartbeat.
Conclusion:
Recommended for occasional reassurance, however, I would buy me the next time more of a Sonoline or so, because I think that a rod is easier to handle and does not smudge as much Ultrasound.