The KickPort T-Ring has an outer diameter of 7.25 inch and an inner, port diameter of 5.25 inch.
In addition to acting as a reinforcement that will prevent vented bass drum heads from tearing and splitting around the port, the T-Ring can be used as a template for cutting a 5.25 inch hole in any head. Many drummers use a 5 to 5.5 inch port to achieve a fuller bass drum sound as well as optimum miking in studio and live situations.
CALIFORNIA PROPOSITION 65 WARNING
WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov.