Fangrui Product Details [professional Assistant]for Removing And Installing Valve Cores In Charged Systems. Leaking Valve Cores Quickly And Easily. Dual Size To Work On Charge Systems Of R410a Or R22 Or Other Retrofit Replacements Systems. [well-made] The Valve Core Remover Installer Tool Is Made Of Solid Brass, Which Is Durable And Wont Rust Easily, And The Metal Knobs Are In Anti-slip Knurling Design, Which Is Durable And You Can Use Them For A Long Time. [time-saving]the Core Grabber Tool Makes It Easy To Insert It Into The Inner Valve, So You Can Control The Core, Neednt To Stop The Machine Or Release The Refrigerant, You Can Remove And Install The Valve Cores Conveniently, Save Hours Of Evacuation And Charging Time. Valve Core Removal Wrench Basic Operation: 1.pull Out The Dead Point On The Stem, Close The Valve On The Tool, Adjust The Joint Of The Tool To The Air Conditioning Interface, And Tighten The Valve On The Air Conditioning. 2.make Sure That The Tool Is Connected Tightly To The Air Conditioning Valve, Then