The balances tab shows the tokens that are supported by the pool, the weighting of the tokens in the pool by value and therefore the pool balance. In Symmetric, a pool can have up to 8 tokens allowing for simple token pairings or more diverse pools such as index funds. The weighting allows for pools to be made up of different amounts of value of each token. For example, a pool could be 95% USDC and 5% new token which means the new token only makes up a small amount of the pool helping to manage risk should that token be highly volatile.