When sourcing from a cement bag factory, you must prioritize material composition and structural integrity. The most common types are AD*Star (Block Bottom Valve) bags and Multi-wall Kraft Paper bags. Ensure the factory uses virgin polypropylene (PP) for woven bags to guarantee high tensile strength. Key metrics include GSM (Grams per Square Meter), typically ranging from 65g to 100g, and UV stabilization to prevent degradation during outdoor storage. For paper bags, verify the bursting strength and the use of micro-perforations for air evacuation during high-speed filling.