Reference for Kilayim 9:5

מוֹכְרֵי כְסוּת מוֹכְרִין כְּדַרְכָּן, וּבִלְבַד שֶׁלֹּא יִתְכַּוְּנוּ בַּחַמָּה מִפְּנֵי הַחַמָּה, וּבַגְּשָׁמִים מִפְּנֵי הַגְּשָׁמִים. וְהַצְּנוּעִים מַפְשִׁילִין בְּמַקֵּל לַאֲחוֹרֵיהֶם:

Clothing salesmen [who display their wares by wearing them] may sell [<i>kilayim</i> clothing] in their usual manner [of sale], provided they have no intention [to protect themselves] against the sun in the sun and against the rain in the rain. The [particularly] observant [salesmen] will suspend them [the clothing] over a stick [behind them and not wear them].

Jastrow