"Rubidium atomic frequency standard, low cost for communications and timing systems, F =50. 255055 MHz, output (0.5 V rms. into 50 Ohm), Set =1E-11 (range =2E-9), warm up time <4 min, Stab =2E-9/year, 2E-11 /day, F Stab =±3E-10 (-5…+50°C), PhN =-100 dBc/Hz (10Hz), -125 dBc/Hz (100Hz), -145 dBc/Hz (1kHz) at 10 MHz, Spur =-60 dBc, Harm =-30dBc, W =338 g, size =37x77x76 mm"