Alright!
https://zapstore.dev/apps/com.pulselibreGet your Pulsetto here, beware, you have to cancel trial right after ordering the device, because they will bill you for the premium app automatically after 14 days!
Get the Fit version, it fits better. And yes, it works, measured on HRV. Good thing if you are chronically stressed and need immune or gut support (both are greatly modulated by the vagus nerve).
https://juraj.bednar.io/pulsetto