I agree with the above comment ^^^ I have a sonokine b Doppler and LOVE it!!! Best investment so far :)I'm 20 wks now and have been using it since I was 11 wks.
I love mine. Especially now that I am 21 weeks, I can find her so fast (it used to be a struggle). I got my Sonoline B on EBay for $42(free shipping and brand new). She often kicks me while I'm listening, and you can hear those movements as well. :-)