This is a steel string set for double bass from Savarez of France, in solo tuning. ●These steel strings are quite soft for steel strings, and their thickness is about half that of Spirocore. By using them in standard tuning, the tension is lowered, allowing for even softer playing. (Use in standard tuning is not recommended, so please do so at your own risk.) ●They also respond to magnetic pickups, enabling powerful and speedy slap playing. *Although this is a solo tuning set (A, E, B, F), it can also be used in standard tuning (G, D, A, E).