It is Nickel Plated Brass, Edward Type. Used For Creating  Vacuum When Connected

Manufacturers and Suppliers of Filter Pump Edward in Algeria, Argentina, Australia, Bahrain, Bangladesh, Belgium, Bhutan, Brazil, Cambodia, Cuba, Cyprus, Denmark, Ecuador, Egypt, Ethiopia, Finland, France, France, Georgia, Germany, Ghana, Hungary, Iceland, Italy, Japan, Jordan, Kenya, Kuwait, Malaysia, Philippines, Tanzania, Uganda