Kester 44 Rosin Core Solder 63/37 .031" 1oz Dispense-Pak Specially packed from Genuine Kester 24-6337-0027 solder 1-ounce Dispense Pak contains approx 24 feet of solder! 67/37 Tin/Lead is most common for electronics work .031" Diameter is most common for electronics work High activity RA formulation