In summary, Kester flux-cored solder wire is available in a wide variety of flux formulas, solder alloys, and wire configurations that will cover any soldering application. No-clean and RMA are intended for electronic assembly of easy-to-solder applications. The 268 was designed for robotic soldering, but can be used in hand soldering applications. RA 44, 48, and 88 are general purpose products that can be used on a wide variety of metals. Water-soluble 331 should be used when cleaning is a requirement or if there are difficult solder joints. The OR-421 is a heat-stable, water-soluble flux that can be used with a torch. Acid-cored and AW are for use in non-electronic applications and must be cleaned after soldering.