4Kingdoms - Advanced Stress Relief - 5.9G

[4Kingdoms]

Just out of curiosity, why trickling stream format?

Back in the day when 3rd generation and 4th generation subs were looped for 12 or 14 hours for 30 days in a row, my go-to was Ultrasonic.
That's why I was drawn to your company.

I'm listening with earbuds so Ultrasonic would be harmful to the hearing.
The hybrid ultrasonic/trickling stream or hybrid ultrasonic/ocean surf would be overkill, because of the usage instructions - less is more.
I think the Ocean Surf sounds too harsh.
Trickling Stream is as gentle as I can get to Silent (ultrasonic).
Plus it is only for 45 mins.
That's a blink of an eye compared to back in the day!!