וַיְהִ֣י מִֽמָּחֳרָ֗ת וַיִּקַּ֤ח הַמַּכְבֵּר֙ וַיִּטְבֹּ֣ל בַּמַּ֔יִם וַיִּפְרֹ֥שׂ עַל־פָּנָ֖יו וַיָּמֹ֑ת וַיִּמְלֹ֥ךְ חֲזָהאֵ֖ל תַּחְתָּֽיו׃ (פ)
Le lendemain, il prit la couverture, la trempa dans l’eau et l’étendit sur la figure du roi, de sorte qu’il mourut. Hazaël s’empara de la royauté à sa place.
Metzudat Zion
This is a thick covering that was brought from it tassels. This Targum Yonatan as Genucha. this is also in Kings 2: 8:15. "and he took the netted piece of cloth" and Targum Yonatan translates it has Genucha.
Ibn Ezra
or in anything made from skin e.g., a coverlet, or a waterskin