The E6R1 Series ChangeDisk Rotating Ring-Disk Electrode (RRDE) tip is often used for electrocatalyst-based research such as oxygen reduction reaction (ORR) experiments. This high quality, precision RRDE tip is ChangeDisk style, which means the disk electrode is interchangeable (disks sold separately). The internal hardware assembly makes use of a consumable part to hold the disk securely in position without leaks, called the E5TQ/E6 ChangeDisk U-Cup. U-Cups work very well, but must be changed frequently (every 4 – 5 ChangeDisk operations is recommended) to ensure proper seal and performance. This tip accepts 5 mm OD disk inserts, from 4 mm thick to 1.5 mm thick. This configuration might be useful to researchers who wish to modify the working electrode surface in space-limiting ways (such as annealing in an oven, drying in a desiccator, or preparing in a glovebox, etc.) and for users who want to analyze/image the disk surface after use (for example, AFM or SEM of the disk surface). Additionally, some users like having one RRDE tip with multiple disk inserts of various preparations and materials to more quickly drop in a different disk electrode on demand. The ring electrode is permanently-fixed into position and cannot be removed. This tip threads into compatible shafts and is not designed to be used by itself. Many other configurations of RRDE tips are also available.