Kester 331 Water Soluble Flux Core Lead-Free Solder Wire - +423 F Melting Point - 0.031 in Wire Diameter - Sn/Cu/Ni/Bi Compound - 24-9574-6403 [PRICE is per POUND] Sale Unit: POUND Brand: Kester Series: 331 Core Type: Water Soluble Flux Core Wire Diameter: 0.031 in