ston + Main Unit ston + Akane The ston+ is a cartridge-type device that can be recharged and used repeatedly. The ston+ is a device that supports the habit of deep breathing. "Deep breathing" acts as a switch for the parasympathetic nervous system, promoting concentration and relaxation. The ston+ was created by focusing on this, and it supports the habit of deep breathing. While encouraging deep, slow breathing, you can enjoy various flavors containing caffeine and GABA. By simply replacing your favorite flavor cartridge, you can use it repeatedly, making it a model that is easy to continue using.