$ETH

It is the native cryptocurrency of the Ethereum blockchain, and its value is generally measured against fiat currencies (such as the US dollar) or against other major cryptocurrencies (such as Bitcoin).

If you are referring to the possibility of having two different amounts of ETH in your possession, or to two different tokens built on the Ethereum network (like a pair of ERC-20 tokens), then the situation is different.

Please clarify what you mean by "pair of ETH coins" so that I can provide you with a more accurate text.