Air permeability 42 cu-ft/hr (1200 l/hr) at a pressure difference of minimum 70 mbarEasy installation drill one 1.6 in (41 mm) Dia holeSealing gasket (nitrile buna-n rubber)Semipermeable membrane inside the plug to filter moisture and dustMounting thread M40 with union nut2.28 in unit dimensions x 0.35 in depth into enclosure