Quiet, corrosion-resistant replacement for outdated ballcock, float ball and rod arm. Withstands harsh water and constant use. Fits most standard tanks including 1.6 gpf models. "Signals" leaks or water waste by automatically turning on/off during periodsof non-use. Backflow preventer guards against toilet water contamination of fresh water supply. Turn-and-lock cap for easy seal replacement - no tools needed. Water level adjusts easily for ideal flush. Easy to install, no special tools required. Meetsall anti-siphon codes.