Daniel Smith Masking Fluid offers excellent coverage and easy-flowing application. If left on a painting for a week, a month, or more, it can still be removed cleanly from all watercolor surfaces with an eraser.
Included are five fine-point tips that can be attached to the bottle and used as a drawing tool to make dots, fine lines, and to save details and highlights.
Brush it on, or apply straight from the bottle. Off-white when wet, it dries to a transparent caramel color.