EASY MOBILITY: A set of four wheels allow you to effortlessly move this base back and forth while two locks keep your shading in place REFILLABLE RESERVOIR & TIGHTENING KNOBS: 2-fold stability system uses a pair of tightening knobs to ensure a secure fit while the fillable base holds up to 123.2 pounds of sand or 37 liters of water. USE IT ANYWHERE: Perfect for any patio, deck or outdoor seating area, with a set of two wheel locks for extra security FITS MARKET UMBRELLAS 6-12FT: A contemporary design blends with most outdoor decorations and fits most market umbrellas sized 6-12ft with poles sized 1.5-1.9in. PATENTED DESIGN: This unique and original design was created by our in-house product developers and is exclusive to Best Choice Products