Large Crucible Torch Melting Gold Silver Kit Set Flux Tongs Stir Rod Smelting Lot 9A Works with gold, brass, silver, copper, aluminum, and more The two ceramic silica crucibles can withstand temperatures up to 2500F (1371C); sizes 500 grams and 750 grams Aalso includes a 6 ounce package of anhydrous casting flux, a 5/16" in diameter x 12" long graphite stir rod, plus a pair of large whip tongs that will securely hold your crucible while your pour and cast your molten metals