Cross Selectip Gel Rollingball Pen Refill, Black, 1 per Card (8523) Black Ink Medium Point Authentic Cross Refill Authentic Cross Refill Medium Point. Black Ink Cross has re-invented writing instruments with jewelry-quality craftsmanship. All Cross writing instruments are unquestionably guaranteed against mechanical failure, regardless of age. Cross offers a range of ball-point refill sizes and colors; Selectip gel rolling balls, porous-points, ball-points and document markers.