This set of patio umbrella base replacement accessories includes 6 pieces: 2 1.85in. outdoor umbrella hole rings, 2 2in. plastic rings (with the smaller rings stored inside the larger ones for easy removal), and 2 M8 40mm classic threaded plastic knobs. Crafted from high-quality black plastic and stainless steel, these parts offer strong temperature resistance, wear resistance, and corrosion protection. They withstand harsh outdoor weather without cracking or fading, preventing friction-related scratches on umbrella poles and accidents caused by loose, unstable poles. Installation is straightforward: simply select the appropriate ring based on your umbrella pole s diameter, fit it into place, then tighten the knobs to secure the base firmly. Suitable for most standard umbrella poles like beach umbrellas and traditional patio umbrellas, these parts work across outdoor spaces such as balconies, backyards, poolside areas and beaches to stabilize your outdoor shade setup.