5 cup, square top break resistant plastic blender jar. Made of ultra strong break resistant Makrolon plastic. Fits all Oster blender models using a 5 cup blender jar with a square top. Fits all Oster Kitchen Center models. This is the most common Oster blender jar type. All Oster Kitchen Centers use this type of jar. Fits all Oster and Osterizer blenders but if your jar is different, you may need OS-060 lid and cap.