One who disassembles a bed in order to immerse it, and one who touches its ropes, are tahor. At what point is the rope [considered] connected to the bed? From when three battim are woven into [the bed]. And one who touches [the rope] from the knot and inward is tamei. [If he touches the rope] from the knot and outward, [he is] tahor. [Regarding] the strands of the knot, one who touches the [part] necessary [for the knot] is tamei. And how much [of the strand] is necessary [for the knot]? R’ Yehudah says: Three fingerwidths.