* Rohde & Schwarz XSRM,BN 238.4011.02, which is a Rubidium Frequency Standard. It delivers a 5 MHz sinusoidal output voltage (1 V EMF) of extremely high spectral purity (S/N ratio >125 dB). The frequency drift due to ageing is less than 1 x 10E-11/month. * Frequency Converter XSRM-Z BN 238.0616.02: high precision frequencies of 10 MHz, 5 MHz, 1 MHz and 100 kHz can be generated. * Battery Power Supply XSRM-Z BN 237.8013.02 is enclosed. Nominal input voltage is 230/115 V, DC voltage of 24 to 28 V as well. The internal battery can buffer the unit for a mains failure time of maximum 1 hour. The Rohde 238.4011.02 is a Rubidium Freq. Std. XSRM Rubidium Frequency Standard 238.4011.02 XSRM Frequency Converter 238.0616.02 XSRM Power Supply 237.8013.02