In State ex rel. Ariz. Dep't of Revenue v. Capitol Castings, Inc., 207 Ariz. 445, 447,9, 88 P.3d 159 (2004), the court adopted a "more expansive definition of machinery or equipment" by applying "flexible and commonly used definitions" of those terms. 207 Ariz. at 450-51,24. In applying these definitions, the supreme court instructed lower courts to: Examine the nature of the item and its role in the operations. Items essential or necessary to the completion of the finished product are more likely to be exempt. The prominence of an item's role in maintaining a harmonious "integrated synchronized system" with the indisputably exempt items will also directly correlate with the likelihood that the exemption applies. Id. at 451,25, The supreme court explained that whether an item is exempt from the transaction privilege tax should be determined not by the material it is made from (metal or non-metal) but rather by the function it performs. Capitol Castings, 207 Ariz. at 451 n.4,25. Of particular note, the supreme court found that "mold wash," a substance sprayed on the mold to prevent the sand from sticking to the casting, was exempt. Id. at 447,3, 451,26. Likewise, the court found that hot topping, a powder employed to keep the molten metal from cooling, was exempt. Id. In Capitol Castings, the court applied the use tax statute, A.R.S. 42-5159(B)(1). 207 Ariz. at 448,11. The language of the transaction privilege tax statute, A.R.S. 42-5061(B)(1), is identical. In Capitol Castings, our supreme court concluded that: Silica sand, chemical binders, exothermic sleeves, mold cores, mold wash, and hot topping qualify for the exemption because they were used directly in and were an integral part of a qualifying process under A.R.S. 42-5159(B)(1). The items functioned the way machinery or equipment might in an integrated, synchronized system within the industry. 207 Ariz. at 451,26.