Paul, you are correct. 9800 and upwards. The 10000CF and dye version were introduced together with the 7500 and 9500, the 10600 Ultrachrome with the x600 range so the 10x00 was the only pressurised model up tot the 9800 range. Yes surprisingly the 4x00 kept that gravitation feeding including the 4900 while the 38x0 has pressurised darts. Ons wondere about the logic.