Treated Hardwood Plugs 3/4" x 4". 5 Gallon Pail/300 Plugs. Poles, Inc. offers a large variety of treated hardwood plugs for sealing inspection and treatment holes. We package our plugs in convenient 1 gallon and 5 gallon containers. Treated hardwood plugs are generally 1/16” larger in diameter than the drill bit size that was used when drilling the hole. Note plug packages are filled by weight and volume calculations and counts should be considered to be estimates.