Extreme Max 3006.8204.2 BoatTector Stainless Steel Long D Shackle - 5/16", 2-Pack ; Size Name Working Load Limit: 1300 lbs., Shackle Size: 5/16. Excellent strength and durability even in the harshest marine environments Not for use in overhead lifting applications. Corrosion Resistant Long Shackles Extreme Max 3006.8213.2 BoatTector Stainless Steel Twist Shackle - 1/4 Marine Grade Stainless Steel D Shackle Working Load Limit: 1300 lbs. Shackle Size: 5/16. See product images for exact measurement diagrams. Available individually or in value-packs of two or four Not for use in overhead lifting applications , Shackle Size: 5/16 Extreme Max Shackles are constructed from marine-grade 316 stainless steel, offering excellent strength and durability even in the harshest marine environments. EXT500 – Extreme Trailers Scotland Working Load Limit: 1300 lbs.