A ring of a person is tamei. [But] the ring of an animal or of utensils and all other [types of] rings [are] tahor. A beam for arrows is tamei. But [a beam] for prisoners is tahor. A collar is tamei. A chain that has a locking device is tamei. [But] one made for tying is tahor. The chain of merchants is tamei [but a chain] of householders is tahor. R’ Yose said: When is this so? When it consists of [only] one link, but if it consists of two [links], or a chilazon was attached to its end, it is tamei.