When sourcing T posts, the most critical factor is the weight per foot, typically ranging from 0.95 lbs/ft to 1.33 lbs/ft. Heavier posts offer greater structural integrity for high-tension fencing. You must also specify the steel grade, usually Q235 or rail steel, and ensure the anchor plate is securely swaged to the post to prevent shifting under lateral pressure. For longevity, prioritize hot-dipped galvanized coatings (ASTM A123 standard) or high-quality powder coating to resist corrosion in damp or acidic soil conditions.