best bluetooth transmitter? incl old post

Hello: what opinions do you have for buying a bluetooth transmitter?
-what I have -- nada, waiting to see what answers I get from audio websites.
-what I want: to plug into the rca speaker output jacks on my yamaha audio receivers, a bluetooth "transmitter." That is, do I have the right term for the equipment? the "transmitter" sends the receiver speaker jack output (rca) to the "transmitter" instead of to a wired (nonpowered) standard hifi speaker. The "transmitter" transforms the signal to bluetooth, which then is read by a (wireless) bluetooth speaker, which plays the sound (music, whatever) as if it was a wired speaker.

-what I want, vol. 2: if I got the term & equipment right, what are good (not top-of-the-line, if any, so $150 or less) "transmitter" products doing that job, and how hard to find & order?

-What I've found: 1mii is a brand (made in china, no phone support listed on web, but has email address). They show on amazon, an mii model B03pro+ for $90, which says "Use B03Pro+ as a Bluetooth Transmitter can also be used to connect Bluetooth headphones or Bluetooth speakers to your existing TV." I would use it to connect for audio from yamaha (audio) receivers.

Does that sound right to you? Do you have experience setting up/using/owning one? If so, how good is it? Other brands/models you might consider worth looking at within my specs? Thank you.