Review on ⚓️ BTG GEAR Two: Premium 15"x20" Red Boat Mooring Buoys - Round Inflatable Balls for Docking, Fishing, Crabbing, and More! by Benjie Swindler

They are delivered deflated and well packaged. Just add air to them and your set. The part that holds the air is made of plastic. If you overtighten, you can loosen the threads, and then it will flow. I've had them for almost a month now and they're still the same size. Seems to hold air well. Rubber is a durable material. The color is bright. The lashing hole is large and can definitely take some abuse. Great find and value. They work great.