Version: 4-piece set. Goalkeeper stoppers are placed on both sides of the goalkeeper on the foosball rods. The goalkeeper stoppers, also known as spacers or positioning rings, are made of high-quality plastic manufactured in Germany and are suitable for all 16 mm rods. Goalkeeper stoppers are used to keep the goalkeeper in place and prevent the rod from being pulled out of the body. The package includes 4 stoppers, each with a hex nut and an internal hex screw. Technical specifications: Outer diameter: 29 mm, inner diameter: 16.5 mm, width: 20 mm. The special feature of these Sportime Guardian goalkeeper stoppers is that the screws and nuts are recessed in the stopper and do not protrude. This goalkeeper stopper fits all foosball tables with 16 / 15.7 mm rods. Compatible with these Sportime Guardian goalkeeper stoppers are the Sportime Guardian rod buffers, which have the same dimensions and the color anthracite. The goalkeeper stoppers press the Guardian rod buffers evenly and gently against the foosball table's rails and sliding bearings. You can use this goalkeeper stopper with the Guardian rod buffers, as well as with rod buffers from other manufacturers.