Uni Jetstream 4&1 Multi-Pen and Pencil is a comfortable rubber grip product that features four colors of super-smooth Jetstream ballpoint inks and a 0.5 mm mechanical pencil. This product combines all the basic writing instruments. The ballpoint components feature Uni's revolutionary low-viscosity Jetstream ink and also features a special spring mechanism that prevents ink leakage, plus a twin ball in the back of the tip to prevent backflow.