- The Pressure Relief Valve Stem Nut has been designed to ensure that an improper tubeless tape job doesn't result in a damaged rim. - If the tubeless seal between tire's air chamber and the rim's cavity is breached, the rim's cavity can become pressurized resulting in a pressurized rim and potential delamination of the rim's sidewall. The Pressure Relief Valve Stem Nut prevents this from happening by creating an escape for the air via fluted reliefs on the inner diameter of the nut. - Air escaping from these ports, indicates a compromised tubeless seal. - Recommended for all tubeless SES wheelsets as well as other brand road tubeless wheelsets. - Each order includes two nuts, enough for one wheelset.