Sturdy Construction: This umbrella clamp and screws are made of sturdy, durable metal, designed to hold your umbrella securely. Easy to install and move, this umbrella stand attaches quickly and securely to most decks, balusters, or railings. The patio umbrella clamp accepts an umbrella pole up to 1.75" thick. The maximum baluster width should not exceed 2.5". The adjustable boat umbrella clamp offers added versatility, ideal for attaching torches, flagpoles, umbrellas, and other outdoor decorations. This space-saving outdoor umbrella stand takes up very little space.