As a matter of definition, dB is the accepted abbreviation for decibel(s). One tenth of the common logarithm of the ratio of relative powers, equal to 0.1B (bel). Further, dBW is the abbreviation for dB referenced to one watt. The decibel is the conventional relative power ratio, rather than the bel, for expressing relative powers because the decibel is smaller and therefore more convenient than the bel. The dB is used rather than arithmetic ratios or percentages because when circuits are connected in series, expressions of power level, in dB, may be arithmetically added and subtracted. For example, in an RF transmission system, if a known amount of RF power, is fed into the system, and the losses, in dB, of each component (for example, lengths of feeder coax, connectors, duplexers, etc.) are known, the overall system loss may be quickly calculated with simple addition and subtraction.