Each validator on the Beacon Chain has two sets of keys: a validator key and a withdrawal key. The validator key is the key a validator needs to sign attestations and propose blocks and the withdrawal key has the power to withdraw staked ETH.

imToken Eth2 staking allows for separate management of the validator key and the withdrawal key. The withdrawal key is managed by the user himself via imToken, while the validator key is imported into the Eth2 client by InfStones, the staking service provider that imToken works with, for node maintenance.