-Fill the base with water or sand through the water injection hole-4 casters are designed for easy movement-2 wheels are lockable for added stability-Convenient built-in handles help to carry the umbrella base easily -High-strength PE material can ensure long-term use-Bottom concave hole design increases the hardness of the surface-A tightening knob for securing the umbrella on the base-Fit most patio umbrellas with 1.25"/1.9" pole diameters-With a maximum water capacity of 36 lbs and a maximum