Galvanized Steel Foundation Sleeve (for Flagpole)The most common type of flagpole installation is the in ground foundation sleeve method which calls for 1' of the flagpoles to be encased in the ground sleeve for each 10' of exposed flagpole height. The diameter of sleeve should be at least 2" greater than the outside diameter of flagpole with the area between the flagpole and the sleeve filled with dry sand. Sleeve with a 6" diameter is supplied with the base plate and grounding spike. Sleeves with