When evaluating KAFOs, prioritize medical-grade materials such as polypropylene or carbon fiber for the shell to ensure a balance between lightweight portability and structural rigidity. The joint mechanism is critical; look for drop locks, dial locks, or stance-control joints that offer smooth articulation and high load-bearing capacity. Ensure the padding is hypoallergenic and breathable (EVA or closed-cell foam) to prevent skin breakdown during long-term use. For B2B buyers, verify that the strapping systems use high-cycle hook-and-loop fasteners capable of maintaining tension over thousands of uses.