Insupen pen needles 31G, 0.25 mm x 6 mm - box of 100 Insupen pen needles are equipped with Pic needles, which is the result of the “indolor® experience” (pain-free technology). The reduced outer diameter, thinner walls, and lubricating treatment allow Insupen pen needles to perform a comfortable, pain-free injection. Insupen is a full range of pen needles in terms of diameter and length and can be used with any injection technique.