A refill adaptor for use in ball point pens essentially comprising a main body (10), comprising of a front part (15) and a rear shank portion (20). The front part (15) and said rear shank portion (20) are rigidly coupled together with a ring member (25); and said main body (10) having a capillary tube (40) throughout its length. The said front part (15) is provided with a front housing (35) for holding the refill tip (55) provided with a ball point (65) for smooth writing, said capillary tube being provided with a ink channel, the internal diameter of which is selected to be about 0.8 mm and the outer diameter of said capillary being selected as about 1.8 mm for easy flow of ink from ink reservoir to said ball point (65).