A low-cost haptic feedback keyboard device for providing haptic feedback to a user for enhancing interactions in a displayed environment provided by a computer. To control pressures, the MEMS apparatus also has a first outgas structure within the first chamber. An amplifier CD in accordance with the invention has low input impedance and a low common-mode output level. For this reason anchorage in tissue which has little mechanical stability is possible. The integral clip includes a deflectable finger which is engaged by the ledge.