If the voltage is transferred unchanged (the voltage gain "Av" is 1), the amplifier is a unity gain buffer; also known as a voltage follower because the output voltage "follows" or tracks the input voltage. Although the voltage gain of a voltage buffer amplifier may be (approximately) unity, it usually provides considerable current gain and thus power gain. However, it is commonplace to say that it has a gain of 1 (or the equivalent 0 dB), referring to the voltage gain.