Is charging with a lower amperage harmful?

i want to use my LG charger to charge my zune. the charger has an output of 5.1V when the zune has a 5V output, i hear that this is ok to charge my zune. however the amperage is different. the amperage on the charger is 0.7A and the amperage on the zune is 1.4A. is it still safe to use the LG charger to charge my zune when the LG has a lower amperage??