uni, makers of the uni-ball line of pens, present the perfect accessory pack for your uni JETSTREAM PRIME TWIST. This pack includes 4 Black JETSTREAM 0.5mm refills. No more smearing! uni JETSTREAM pigment-based ink provides deep color and dries almost instantly. Our exclusive hybrid formula is our most innovative ink for unparalleled smoothness and crisp, vivid lines. Combining the smooth flow of gel ink and the crisp lines of a ballpoint, uni has developed a hybrid ink that penetrates paper easily – without smearing, fading, or washing away. The combination of pigment and new color material provides black density 2x that of conventional ink.