The ESSTAC 7.62 AK Triple KYWI, Mid-Length pouch is no different than the standard ESSTAC 762 pouch. The insert is made from kydex and is heat moldable if more or less tension on your AK magazine is desired as an end user modification. There are 4 rows of webbing on the back of the pouch. You only use the Top 3 rows of webbing when mounting (not 4).
NOTE FROM ESSTAC: While they have always fit 762x39 AK mags we do not think they are a perfect fit due to the obnoxious curve of the AK magazine and locking lug; we have never fully recommended them. The pouch works and we even run them personally but your mileage may vary and we do not guarantee a "perfect for everyone" fit.