There are four things that Rabban Gamliel deems capable of becoming tamei and the Sages deem tahor: The metal cover of a householder's teni, and the hanger of a strigil, and unfinished metal utensils and a tray that split into two. But the Sages agree with Rabban Gamliel in the case of a tray that split into two [pieces], one large and one small, [that] the large [piece] is [capable of becoming] tamei and the small [piece] is tahor.