Viper RT300S Foam Gun Foam SprayerViper RT300S Dust fill the container with full strength coil cleaning concentrate. No mixing or pre dilution. Simply connect to any garden hose. Dial in a dilution ratio, aim, and fire. Foam cleaning is the most efficient method of coil cleaning. Typically, one gallon of coil cleaner will produce enough foam to clean five, 5 ton condenser coils. For best results, we recommend using our high foaming concentrates, Viper Heavy Duty or Viper Brite.