Approved Home Dopplers?

Melissa💗 • Rainbow baby born in 2016, then another miracle born in 2018! 🙏🏼 Currently just found out pregnant with baby #3! Fingers crossed all is well! ❤️
Hi all :) So I am 16 +4 today and have my next u/s at the end of month (i haven't been seen since then 😩) needless to say I am going stir crazy and and so was going back and forth on whether to invest in a home Doppler. There are so many opinions on them so I'm stuck. My main concern being that none seem to be FDA approved... Are there any in fact approved to use? Any input is welcomed :)