Lead-free acid-resistant glass composition includes 5-25% of SiO2, 4-30% of B2O3, 7-30% of ZnO, 15-70% of Bi2O3, 0-15% of Al2O3, 5-20% of BaO in weight percentage, and being substantially lead-free. The system includes a housing and at least one pipetting head disposed within that housing for aspirating and dispensing a liquid. In addition, a predetermined processing operation is carried out with respect to the surface while an irradiation position of the laser beam is moved in a horizontal direction. A keypad contact array and a display electrode pattern may be included on the first surface of the substrate. An embodiment of the invention is directed to a telephone headset amplifier system with a noise blanking or squelching capability, which attenuates the incoming audio signal when the incoming signal exceeds a predetermined threshold.