-2011- Gensenfuro 28 |link|

Forms a microscopic salt blanket over the skin to prevent sweat evaporation.

Based on the reference to " -2011- Gensenfuro 28 ," this likely pertains to the Gensenfuro (源泉風呂) -2011- Gensenfuro 28

: At 28°C, the water feels chilly initially. Onsen enthusiasts often practice "alternating baths" (kogo-yu), switching between the 28°C cold source and a heated bath to stimulate circulation and "reset" the body. Forms a microscopic salt blanket over the skin