DorBuphan Patio Umbrella Holder Stand, Universal Deck Umbrella Holder, Adjustable Sun Umbrella Clamp for Decks, Docks, Pontoons, Picnic Tables. 【Widely Use】: This umbrella deck clamp is perfect for patio unbrella securely to most railing, fence, bleachers, benches, tailgates, boats and more.
eBay