Flexible black rubber seals the lid to the cup for leak proof seam. Makes your lid like NEW again! This is the CORRECT way for this part to work! Therefore your old gasket will look like a circle shape when you remove it, but it was an oval when it was first made!

Flexible black rubber seals the lid to the cup for leak proof seam. Makes your lid like NEW again! The gaskets WILL fit 30 ounce ramblers fits YETI, fits Ozark Trail, fits Rocky Mountain, fits Polar Drifter, fits SIC, and MANY more.