The Nano Atomic Clock (NAC1) from AccuBeat is a Time and Frequency Standard with Frequency 10 MHz, Frequency Stability ±1 ppb, Phase Noise -150 to -86 dBc /Hz, Short Term Stability 0.02 to 0.2 ppb, DC Supply 3.3 V. Tags: Board Mount, Frequency Standard. More details for Nano Atomic Clock (NAC1) can be seen below.