The Masking Fluid Pen works like a resist pen. Now you can make precise, controlled lines, dots, or area coverage with ease. No need for a brush. Simply apply the masking fluid over the area to be protected and let dry. Once dry, paint over the protected area and let dry again. Now, peel off the dried mask or resist to reveal the uncolored area. The Masking Fluid Pen dispensing tip is 1/2". The unique cap/wire system ensures a continuous flow of liquid from start to finish, always precise and controlled. No cleaning required.