The GPS-12R/HS from Pendulum Instruments is a Time and Frequency Standard with Frequency 1.544 MHz, 2.048 MHz, Frequency Stability 0.02 ppb, Stability over Temperature 10 ppb, Phase Noise -145 to -90 dBc/Hz. Tags: Benchtop, Frequency Standard. More details for GPS-12R/HS can be seen below.