Hi there,
Here some General but very thorough research on the subject
https://www.mdpi.com/1424-8220/17/4/673
and also a link to what is available in general.
Amazon.com
HTH
GL 
PJ 
Have you seen this video , The wristBand turns out to be the show stealer in tech in my opinion, its a clue a good one EMG is cool and materials that can detect those levels can do amazing stuff .
