Introducing the Signite Hydraulic Tank Breather Cap 1/2 InchNPT – Efficient Air Filtration for Optimal System Performance The Hydraulic Tank Breather Cap 1 Inch NPT is a must-have component for any hydraulic system, designed to ensure optimal performance and longevity. This high-quality breather cap effectively controls the air entering and exiting your hydraulic tank, protecting your equipment from harmful debris and maintaining a clean operating environment.