Zorb sandwiched between 2 layers soft bamboo.
According to manufacturer:
ZORB absorbs 10x it's weight in less than half a second -- that's 20x faster than cotton, bamboo or hemp. Zorb is made with a combination of wicking fibers and highly absorbent fibers which reduce compression wicking.
Check my shop for other sizes of inserts and doublers one of which is shown in pciture #3.
Please convo me if you would like additional quantities.