Fence Armor Metal Post application installation instructions:

• For 2 x 2 metal posts Fence Armor is designed to simply click lock
  around the existing posts. Take each half unit and snap the
  corresponding notches to fasten to the post. No Drilling required.
  

Fence Armor Round application installation instructions:

• The Fence Armor Round application was designed to follow the bend
  on a rounded post. Standard rounded posts have a diameter of 3.5 to
  5 inches. If your post is larger, two or more segments of Fence Armor
  Round may be required to cover the post. Sink the fastener of your
  choice into the center hole, then wrap until the two ends meet and
  fasten securely to the post.

For tree protection it is important NOT to affix the product directly to the
tree, there must be approximately a quarter to half an inch of room for the
tree to breathe. By fastening the center holes together with a bolt the
necessary length and height can be achieved to reach the desired
diameter.

For more unique shapes Fence Armor Round is malleable and can be
formed to fit most shapes.

Slide Fence Armor over the bottom of your existing post, at the middle of
the centre line of your grass trimmers path. Place a second unit on the
opposite side of the post, over-lapping each unit until slot and side holes
meet. Fasten with 1 ¼ to 1 ½ inch long galvanized nail or outdoor rated
deck screw. If side holes are not accessible, use the front hole to fasten
with the same type of fastener. For best results stain or waterproof
untreated posts before installing Fence Armor. If required, due to ground or
fence level, you may stack Fence Armor to increase desired protection
area.