The market leading pen contains a unique ink flow system that ensures continuous flow and high writing performance until the very last drop. It features a see-through ink chamber so that you can monitor how much ink is left.Uni-ball Eye pens feature Uni Super Ink thats permanent once dry so that your signature is secure. Uni-Ball Eye Pigment Ink Rollerball Pens – Fine UB157 are a Fine 0.7mm rollerball pen. See-through ink chamber, waterproof pigment ink. Stainless steel tip. Non-refi llable.