Post Shields - ( 3.5" L x 3.5" W x 4" H Black): Protects mailbox and fence posts from grass trimmer damage.

Post Shields Post Protector 4x4 (3.5"x3.5") - 4"H - Protects Your Mailbox, Deck & Fence Posts from Damage by Lawn Maintenance Equipment - Fits Wood & Metal Posts - No Tools, Screws or Nails Needed

Wanhork 304 Stainless Steel Adjustable Post Protector (Range 3.3-6in), Protect mailboxes, Deck and Fences from rain and Damage to Maintenance Equipment (1set, Black)