An audio amplifier system having improved power efficiency by wasting less power in its bias voltage circuit. The generator employs an air filter to remove particulates and aerosols from the incoming air. The air-packing device is folded after the product is inserted in the pocket and installed in a container box. According to one aspect of the present invention, a clearly discernible feedback is provided to clearly indicate engagement between the ground-engaging member and the sole. The antistatic device can include a first switching thin film transistor in which an active layer is formed of oxide, a second switching TFT in which an active layer is formed of oxide, and an equalizer TFT in which an active layer is formed of amorphous silicon. The material includes between about 3% and about 25% by weight of fibrillated microfibers, between about 20% and about 75% by weight of reinforcement microfibers, and between about 15% and about 60% by weight of a binder.