[If] the rova becomes tamei, the rova and its exterior are tamei, [but] the half-rova and its exterior are tahor. [If] the half-rova becomes tamei, the half-rova and its exterior are tamei, [but] the rova and its exterior are tahor. [If] the exterior of the rova becomes tamei, the exterior of the half-rova is tahor; [these are the] words of R’ Meir. But the Sages say: We do not divide exteriors. And when one immerses [this utensil], he must immerse it in its entirety.