The main sugya is Bava Metzi'a 27a (last line on page)–28a, though there is a cross reference to it earlier, on page 27a.

In the whole of the second chapter of Bava Metzi'a (cf. supra, p. 34) it is accepted as the rule that a lost article must be returned by the finder to the one who claims that he lost it, if the latter substantiates his claim either by producing two witnesses that it is his or by declaring the distinguishing marks of the article. These are known as simanin (or, in the Hebrew form, simanim, sing, siman). Simanin are thus treated as a reliable means of identification. But it is not clear whether reliance on simanin has Biblical warrant – simanin de-oraita – or whether such reliance is by Rabbinic enactment only – simanin de-rabbanan.

The sugya begins with the stock formula when a problem is set: ibbaye le-hu, ‘they [the anonymous scholars] set a problem’. The problem is: ‘Are simanin de-oraita or de-rabbanan?’ The practical difference, the Talmud continues, is whether or not a bill of divorce (get) can be returned when its simanin have been stated. A husband sends a get, which has to be written specifically for that husband and wife (see supra p. 24), through his agent, to deliver it to the wife and the agent loses the get but a get is later found. The agent describes the simanin of the get he has lost and these coincide with the simanin of the get that has been found. Can simanin be relied onsufficiently to enable the agent to take the get and deliver it to the wife?