The Kester line-up of available flux-cored solder wire at DigiKey is shown here in order of increasing activity level, along with the intended applications and features. The 245 and 275 are popular formulas for no-clean electronics assembly applications. 245 is generally a leaded alloy and 275 is lead-free, although there are some exceptions. The 268 wire is available in both leaded and lead-free and is designed for use in robotic soldering applications where spattering of the flux during the soldering process may be an issue. It is also popular for use in hand soldering applications where a zero-halogen designation is desired. RMA formulas 285 and 282 are generally available in leaded alloys; 282 is a halide-containing flux that will give the highest activity level for an RMA. RA rated 44 (leaded) and 48 (lead-free) are general purpose cored wires that will solder to a wide variety of finishes. RA rated 88 is a product that has the highest activity of a rosin-based flux. Water-soluble 331 is available in both leaded and lead-free alloys and should be used if a high level of activity is required and the assembly must be cleaned after soldering. OR-421 is very heat stable for use with a torch in applications such as refrigerator coils. The acid-cored wire is an inorganic acid flux that will solder excessively oxidized and difficult-to-solder metals. Finally, AW wire is for industrial applications where a flux-cored solder wire is desirable. Inorganic acid flux is extremely corrosive and should not be used for electronic applications. Like 331, inorganic acid residues must be cleaned after soldering otherwise they will be corrosive.