שימוש במכשיר שמיעה בשבת

Someone in our family has a new hearing device called, I think, "walk and talk". Instead of a small hearing aid that fits in the ear, this device has earphones (similar to those on a walkman) connected by wire to a hand-held small box. That small box is connected by wire to a microphone into which we speak. The whole system is powered by two batteries, that do not need re-charging over the course of a shabbat. The technician who prepared the device assures me that the electronics are the same as in a regular hearing aid. Can such a device be used on Shabbat?