Skirted base hides wheels for an improved aesthetic appearance, and bolt to bottom of ERK Series rack systems. Skirted caster bases add 4 to overall rack height. Skirted base looks good and protects caster area. Robust steel construction with black powder coat finish. Includes (4) 3" pre-installed non-locking fine floor swivel casters. 700lbs weight capacity. UL Listed in the US and Canada.