Oatey 10616 Hercules Climate Smooth Soldering Paste Smooth, premium quality, petroleum-based flux. Formulated for use in extreme climate temperatures all year long. Self-cleaning; lead-free formula. Will not lose its consistency in high or low temperatures. Meets Commercial Item Description A-A-51145 (supersedes Fed. Spec O-F-506). Smooth, premium quality, petroleum-based flux. Meets Commercial Item Description A-A-51145 Formulated for use in extreme climate temperatures all year long. Self-cleaning; lead-free formula Will not lose its consistency in high or low temperatures