The document discusses an upgrade to second stage regulators on self-contained breathing apparatus (SCBA). The new regulators have the same manual override and reset buttons in the same locations under a new exterior. The upgrade improves the seal between the regulator and facepiece mask, reducing slight air leakage when the hose is pulled forward. The manufacturer discovered this potential minimal leakage issue and developed the upgraded regulators to address it, while noting the original regulators remained safe and effective. The upgrade is being implemented on frontline SCBAs.