This item contains (4) individual gallons of RYDLYME Marine Biodegradable Marine Descaler. This product is to be diluted 1:1 with water and water only prior to use. For periodic maintenance, it may be diluted up to 1:3 with water. It is also available in single gallon quantities. No ready-to-use item is manufactured. RYDLYME Marine works most effectively when circulated through an application such as a raw water cooling system, oil cooler, or A/C condenser in order to rapidly dissolve any unwanted marine fouling of water deposits. RYDLYME MARINE is safe on virtually any metal or material in water operated systems except for zinc and magnesium. Make sure to blank anodes or plan on replacing them after cleaning the cooling system on a marine engine. For complete instructions, SDS, and Specifications please review the available Technical Documents below or visit www.RYDLYMEMarine.com for further information and to contact a product specialist.