It's a "stone brush" 石刷 shíshuā. (Alternatively "It's a number!" 是数啊 shì shù a, but then pinyin orthography requires writing it as "Shishu'a" with an apostrophe

It's a "stone brush" 石刷 shíshuā. (Alternatively "It's a number!" 是数啊 shì shù a, but then pinyin orthography requires writing it as "Shishu'a" with an apostrophe in front of the third syllable.)