I assume you are asking about #40 Pocket Drill Cloth.
For starters, it is made of 100% Cotton.
Secondly, it is woven using three threads making for a very tight weave, even tighter than twill woven fabric. Ticking is twill and the cloth is woven from two threads.
Third, it is consistent in thickness, measuring 0.017 to 0.018" in thickness. Once washed and dried in a hot dryer, the weave tightens up but does not really increase in thickness.
Fourth, it takes lubrication well whether it is for use as a damp patch for use after wiping between shots or as a wet patch on the ball for those that do not wipe between shots.
Finally, it compresses into the grooves with the matching ball for great accuracy whether for target shooting or hunting.