Dual unit milk crate dolly's polyethylene construction won't rust or corrode. 3" swivel casters. Dual units hold crates side by side. Height includes casters. Fits 13"Wx13"D milk crates. 300 lb. load capacity. 161/8"Wx291/4"Dx83/8"H exterior. 1311/16"Wx263/4" interior. 16 lbs.