Amazon.com : Ashman Ground Screw (4 Pack), No Dig, U-Model Screw in Post Stake - 27" Inch Long, Fits Standard 4x4 (3.5" X 3.5" Inch) Great for Mailbox Posts. : Patio, Lawn
Amazon.com: Eapele 4x4 Wood Fence Post Anchor Base, 13GA Thick Steel and Black Powder Coated,Come with Wood Screws and Concrete Anchors : Patio, Lawn & Garden
GRK Fasteners 5/16 in. x 4 in. Star Drive Round Head Rugged Structural Wood Screw (45-Piece per-Pack) 112225 - The Home Depot
Amazon.com: Antsky 4×4"(Actual:3.5×3.5inch) Post Stainless Steel Flange Anchor Base with Screws for Deck Railing,Black Finish (1 Pack) : Tools & Home Improvement