When evaluating jack stands, the most critical factor is the rated capacity, which must always exceed the weight of the vehicle being supported. Look for high-grade forged steel or heavy-duty cast iron construction to ensure structural integrity. Key features include a wide tripod or four-legged base for stability, a large saddle area to prevent slipping, and a multi-position ratchet bar or pin-lock system for secure height adjustment. For professional environments, prioritize models with welded steel frames over bolted ones to minimize points of failure.