3.79 litre Concentrate, with Salt-Attack’s unique Mixing Unit included. The Mixing Unit connects to a garden hose for dispensing. No need to purchase the Mixing Unit again. 946ml and 3.8 Litre refills can be purchased separately Comes with international quick fit hose connectors to connect mixer to hose and motor flushers/engine TO FLUSH ENGINE put 40-60mls (min 1/2 – 3/4 cup) Salt-Away concentrate in mixer cup for engines up to 90 hp, and for engines 90hp-300hp use 80mls (full cup) to flush your engine, wash boat, trailer,fishing and diving gear, Instructions included in kit Handles extreme water pressure up to 120 psi MIXES AT UP TO 512 PARTS WATER TO ONE PART CONCENTRATE ! THAT’S 1940 LITRES !! The Salt Attack spray gun also works great with Marine Washcoat and Shine!