Home Doppler

My husband Matt recently purchased an at home doppler from fetaldoppler.net. We previously had rented one from babybeat.com for both the boys pregnancies but this time for the same price of a one month rental we could buy one.... So we desided to give it a shot! I am not sure if it is lesser quality but I was able to find what I think is our baby's heartbeat at 8 weeks and 3 days pregnant. I did think the heart rate might be a little higher since this is what it was at our 7 weeks ultrasound but I don't know.