Roller- and ballpoints regulate the ink flow via the ball in the tip, which simultaneously acts as a limitation; the sharp edges of the tip lead to tight tolerances in the writing angle. Failures can indicate a too dry refill or a slightly bent tip edge. A switch to another refill, e.g. a broader ballpoint refill or a Schmidt fineliner refill, can improve the ink flow and ease the angle range, since the 162 barrels accept both rollerball and fineliner refills.