Heavy duty industrial bags are produced using sack kraft which is made of basis weight ranging from 50 GSM to 130 GSM which is converted into products such as grocery and retail bags, multi-wall shipping sacks and specialty papers. Kraft paper bags consist of 2-4 plies with polyethylene in middle layers. It is made of softwood kraft pulp, which imparts a high degree of strength to the paper due to the long fibers.

Sack kraft paper is now so strong that 3-ply bags are very seldom necessary. Instead, 2-ply bags made of strong, high porous grades (e.g. 2-ply 80 GSM Advantage Select) are designed to hold up to 50 kg of cement. For 20 kg to 35 kg bags, 1-ply 110 GSM (Advantage One) bags have proven to be an innovative, very economical and successful solution.