From the manufacturer's website: ■ Significantly extends the life of strings (especially wound strings). ■ Improves string slide, making them easier to play. ■ Improves slide on the nut and saddle, stabilizing tuning. ■ How to use: 1. Apply 1-2 drops of COSMOTONE to a suitable cloth and thinly coat the entire string. (It's easier to apply before stringing the instrument, but it can be done afterward.) 2. Let it dry for about 20 minutes. 3. The effect lasts, but reapply if you want to improve the slide further.