STURDY 4-PLATE DESIGN: Made with interconnecting pins to lock your umbrella base in place and secure it for hours of enjoyment (Note: Crossbar base not included) EASY-TO-FILL SPOUTS: Each plate is built with a fill spout and a twist cap to create a water-tight seal for quick and easy refills, ballast disposal, and relocation HIGH WEIGHT CAPACITY: The plates can hold up to 13.2 liters of water (per plate) or 38.9 pounds of sand (per plate), so your patio umbrella will have a reliable anchor point HEAVY-DUTY & WEATHER-RESISTANT: Made of HDPE plastic to withstand impact and constant movement, and treated with a weather-resistant coating OFFSET UMBRELLA ESSENTIAL: Provides a solid anchor for compatible umbrellas and protects them from incidental damage caused by falls and harsh weather (Search: SKY5681 or SKY5248)