Review on Durable Stainless Steel Fasteners with Optimal Diameter by George Johnson

These pins work well. Stainless steel with a large finger ring. I attached some small cables to the pins so they wouldn't get lost. I use a pin to attach the umbrella to the weight. We moved them around a lot in the pool and it's nice to just pull the pin and pull out the screen instead of unscrewing the bolt. So you can switch off quickly in windy weather and when moving tables.