You know Tinctures. Essence is in that neighborhood. Same smooth feel, rayon/nylon instead of silk/nylon, and friendlier on the wallet. A little less precious. No less useful.
It plays smooth. Holds tension without asking for attention. The kind of string you reach for when you want the yo-yo to do the work and the string to stay out of the way.
Good string doesn’t have to cost like it.