Hand-turn Knob to Fix the Umbrella: The round base design is big enough to hold the umbrella, features two hand-turn tightening knobs for securing umbrella to the base.Double lock design, one hole inside and one knob outside which could fix your umbrella tight.Plastic inserts on top of steel pipe fit for Φ1.5" (38mm) or Φ1.9"(48mm) umbrella poles.
