Product Information: The E-Ring is an easy-to use external overtone control ring which “floats” on the surface of a drum head. It removes overtones and flattens the drum head’s sound and allows for easier tuning. Product Features: Pack of 10 E-Rings for 13″ drum heads Designed to eliminate overtones, flatten the drum head’s sound, and allow for easier tuning 1.5″ diameter Also available in Prepacks to fit the most common drum set configurations All Evans accessories are designed, engineered and manufactured to the most stringent quality controls in the industry