4″ x 4″ Plastic Post Base Skirt & Post Cap Adapter

Our plastic post plate covers are a quick and easy way to upgrade your outdoor space. They’re the perfect way to complete a fence or deck post. In only minutes, you can add style to your property while protecting your posts from cracking, splitting, and weathering from the elements.

UPC CODE: 664723101989

This long lasting post cap skirt and adapter is an easy way to instantly improve your outdoor space.

  • The rigid plastic construction of our post cap adapters protects your post from weathering and seasonal elements while its modern yet timeless look elevates any environment.
  • On top of protecting your post, its elegant and simple features complement most residential, commercial, industrial fencing, and landscaping projects. Install them on wooden, iron, composite, vinyl, or aluminum posts. Their design versatility makes them perfect for contractors and DIYers and ensures they’ll be the perfect addition to your backyard.

Fits over a 4” x 4” nominal post

  • Understanding Post Cap Sizes:
    • When a post cap fits a nominal or dressed post, the post measures 1/2″ less than the measurement listed.
      Example: a nominal or dressed 4″ x 4″ post cap fits a post that measures 3.5″ x 3.5″
    • When a post cap fits a rough lumber or undressed post, the post size is the same as the measurement listed.
      Example: a 4″ x 4″ rough lumber or undressed post cap fits a post that measures 4″ x 4″


  • MATERIAL & FINISH | This long lasting post cap skirt, adapter, and collar is made from black, rigid plastic and features a satin finish
  • PROJECT VERSATILITY | Simple yet elegant, its two-piece design complements a wide variety of projects
  • TOUGH DEFENDER | Extends the life of your fence or deck post while preventing cracking, splitting, and weathering.
  • HIDE PROJECT IMPERFECTIONS | Use as a post base cover to hide exposed nuts, bolts, and uncut ends
  • PERFECT PAIR | Use as a post cap adapter with any of our 6″ x 6″ caps (required and sold separately) to top your post
  • BETTER TOGETHER | Use two covers together to create a post collar that hides joints and seams from connected post sections.
  • POST PROTECTION | Protects your posts from the accidental scuffs and scratches that may happen with seasonal maintenance
  • WHAT’S INCLUDED | One (1) post cap adapter/collar with fasteners
  • COMPATIBILITY | Compatible materials include wood, vinyl, composite and more
  • EASY INSTALL | In addition to the beauty and post protection it offers, the installation process is quick and intuitive.
  • LOW MAINTENANCE | Our post plate covers clean easily with soap and water, making maintenance simple


  • UV-Protected | prevents fading and discolouring caused by the sun’s harsh rays
  • Rust-Resistant | its durable rigid plastic construction prevents peeling and blistering
  • Weather Protected | designed to last through North America’s harshest conditions
  • ACQ wood compatible
  • Retrofits to existing posts
  • Ideal for use in moderate traffic locations
  • Ideal for contractors and DIYers
  • Novice skill set required for installation
  • Estimated installation time: 5 minutes
  • Prior to construction, check with your local municipality for building code requirements in your area.
  • Perfect for residential, commercial, and industrial use
  • Materials and packaging are fully recyclable
  • Limited one (1) year warranty.