Kester 44 Rosin Core Lead Solder 63/37 .020" 1 lb. Spool Kester 44 Rosin Flux is an activated rosin formula for use in flux-cored solder wire. Kester 44 Rosin Flux has virtually dominated the field of activated rosin core solders for well over four decades. An outstanding performance feature of this flux is the "instant-action" wetting behavior. The high mobility and fast-spreading action of this flux results in more reliable production line soldering.Features:Kester "44" Item Number 24-6337-001067/37 Tin/Lead, .020" Diameter is common for fine-pitch SMT and SMD electronics work High activity RA formulationExcellent solder-ability to a wide variety of metallizations Industry standard for decades Standard Core 66 (3.3% flux) Solder iron tip temperatures between 315-371°C (600-700°F)Flux residue is non-corrosive and non-conductive Factory fresh, NOT SURPLUS. Shelf life 2 years from DOMA few warnings and cautions:For industrial use onlyWe can not offer advice on a specific application. For use by experienced electronics technicians User assumes all risk for application.Any warranties are limited to replacement or refund of product.Always wear safety glasses when working with soldering equipment and materials Always use adequate ventilation when working with soldering equipment and materials Avoid breathing flux fumes emitted during soldering.Flux fumes may cause pulmonary irritation or damage.This product may contain chemicals known to the state of California to cause cancer and/or other reproductive harm.