The figure in a receiver's specifications which indicates its sensitivity is the:

Receiver sensitivity is a measure of how well a receiver can pick up and make sense of very weak radio signals. It tells you the minimum signal strength required at the antenna to produce a readable audio output over the background noise. In radio specifications, this is expressed as the RF input signal voltage (usually in microvolts) needed to achieve a specific signal-to-noise (S/N) ratio, such as 10 dB. A lower microvolt number indicates a more sensitive receiver because it requires less signal to produce clear audio. Common distractors like "bandwidth" refer to selectivity (the ability to reject adjacent signals), not sensitivity. Similarly, audio output in watts measures the power of the internal amplifier, which has nothing to do with the receiver's ability to detect faint incoming RF signals.