Reference for Kelim 18:9
מִטָּה שֶׁנִּגְנַב חֶצְיָהּ, אוֹ אָבַד חֶצְיָהּ, אוֹ חֲלָקוּהָ אַחִין, אוֹ שֻׁתָּפִין, טְהוֹרָה. הֶחֱזִירוּהָ, מְקַבֶּלֶת טֻמְאָה מִכָּאן וּלְהַבָּא. מִטָּה מִטַּמְּאָה חֲבִילָה, וּמִטַּהֶרֶת חֲבִילָה, דִּבְרֵי רַבִּי אֱלִיעֶזֶר. וַחֲכָמִים אוֹמְרִים, מִטַּמְּאָה אֵבָרִים, וּמִטַּהֶרֶת אֵבָרִים:
A bed, half of which was stolen or lost, or one which brothers or joint owners divided, becomes pure. If it is restored [to its former state], it is susceptible to impurity from that point onward. A bed may contract impurity when all its parts are bound together and be purified [through immersion in a mikveh in that state], the words of Rabbi Eliezer. But the sages say: it contracts impurity in its individual parts, and must be purified [by immersing] its individual parts.