4 oz mechanic in a bottle, cleans engines with issues related to varnished carburetors, water in the tank, carbon deposits, ethanol, & old/poor quality gas, removes all varnish in the fuel system without having to remove the carburetor from the machine, contains rubber & plastic conditioners, revitalizes old fuel, safely dissolves varnish/shellac, anti-corrosive/metal deactivator, carbon cleaner, octane improvement, fuel stabilization, high temperature detergent, upper cylinder lubricity, not a replacement for 2 cycle oil.