Hey mechanics and equipment repair folks! If you're rebuilding a hydraulic cylinder and need a reliable rod seal, take a look at these. They're brand new U-cup rod seals, specifically the UN type, and they come in a range of sizes from 4mm all the way up to 28mm shaft diameter. They're made from PU (polyurethane) material with fluororubber elements, which is a fantastic combo for hydraulic applications. Why? Because these seals can handle some serious pressure—up to 35 MegaPascals (that's over 5000 PSI!). They're also rated for a linear speed of 0.5 meters per second and a wide temperature range from -35°C to 100°C (-31°F to 212°F). So whether you're working on a log splitter, a dump truck cylinder, or industrial machinery, these seals are built tough. The brand is Goo Better, and they're sold as a type of oil seal. They come in their original packaging, new and unused. Installing a fresh U-cup seal is key to preventing fluid leaks and keeping your cylinder's pressure where it should be. Just make sure you order the correct size for your piston rod. These are critical little components that make a huge difference in performance. No fancy MPN or UPC, but the specs are what really matter here. Keep your hydraulic systems sealed up tight and running smoothly!