Rio Brands Beach Umbrella Sand Anchor. This rust-proof nylon and fiberglass construction anchor securely holds beach or picnic umbrellas, backyard game poles, flag poles, and other items in winds up to 30 mph. It easily screws into sand or dirt and fits all beach umbrellas up to 7-1/2' with poles up to 1-1/4" diameter. The handle design allows for easy twisting, while the sturdy resin tightening screw and threaded end provide sand stability.