Cla-Val 583 Series “Tite Seal” foot valves provide years of trouble-free operation at low or high pressures. The special Buna-N® seal allows initial contact to the metal plug, for zero leakage, then as pressure builds, the Buna-N® seal is compressed only slightly until the plug fully contacts the metal seat preventing further compression of the Buna-N® seal. In this manner, the seal cannot be damaged from compression and pump prime is always assured.