A whorl [made] of metal, R’ Akiva rules it tamei, but the Sages rule it tahor. And a plated [whorl] is tahor. A spindle, a distaff, a rod, a symponia, and a flute, [if they are made] of metal, they are tamei. But [if they are] plated, they are tahor. [However,] if a symponia has a receptacle for [valves resembling] wings, it is tamei in either case.