Yes it is, if you send it a real balanced signal on the XLR connector. It will take the two input signals from the XLR and amplify both of them (using two separate amplifiers) and combine them at the output. If you use a RCA input it will "copy" the input for the two amplifiers.

It is possible to have a product with an XLR input with a balanced input signal, but most of the time the signal is converted into unbalanced right as it comes in then sent to a single amplifier.