When selecting aluminum jack stands, the most critical factor is the Load Capacity (Tonnage). Ensure the rated capacity (e.g., 3-ton, 6-ton) is clearly embossed on the unit. Look for High-Grade Aircraft Aluminum (6061-T6) which offers a superior strength-to-weight ratio compared to steel. Additionally, verify the Base Design; a wide, flat base is essential to prevent sinking or tilting on softer surfaces. Check the Pin-Lock Mechanism—it should be made of hardened steel with a safety chain to prevent loss, as this is the primary failure point under load.