I have the 3ml x 100iu pen but the pen is a pain in the ass to use... my plan is to extract from the chamber with my own pins... if someone could double check my math that would be great... if I wanted to pull 10ius that would be 3 ticks on my slin pin or .03ml correct? im used to humilin r which is 10ml x 100iu and the math is very easy