This specification covers the performance requirements for NPN, silicon, low power, ultra-high frequency transistors. Four levels of product assurance are provided for each device type. Two levels of product assurance are provided for unencapsulated devices as specified in MIL-PRF-19500. RHA level designators "M", "D", "P", "L", "R", "F", "G", and "H" are appended to the device prefix to identify devices, which have passed RHA requirements.