4 leg 28" diameter polished base.
No rocking feature.
Good class 3 quality gas cylinder (better than class 2).
2" chrome non-marking casters, full hood, and dual wheels for any type floor.
Bolt hole slots are 1/4" wide X 3/4" long.
Simply insert without tools the gas cylinder into the center hole of the 4 leg chair base. Just sitting in the chair several times will make extremely tight and require tools to remove.
7” x 7” 360° swivel only seat plate.
Attach seat plate to chair seat bottom using 5 3/8" elongated holes in each corner of the 7" seat plate. Holes can also be used at 5" minimum to 5 3/4" maximum.