EIA-172-B:1975

This standard covers insulated, fixed resistors having a composition resistance element and capable of full load operation at an ambient temperature of 70°C. This standard describes minimum *limits of performance commonly observed in commercially available products, There are products available with higher levels of performance for some characteristics.
CLASSIFICATION
Type Designation - The type designation shall be in the following form and as specified in 2.18:
Style - The style shall be identified by a three letter symbol 'RRC' followed by a two-digit number; the letters identify insulated, composition, fixed resistors, and the number identifies the she and power rating of the resistor. See Table II.
Resistance - The nominal resistance value expressed in ohms shall be identified by a three-digit number; the first two digits represent significant figures and the last digit specifies the number of zeros to follow. When values less than 10 ohms are required, the letter 'R' shall be substituted for one of the significant digits to represent the decimal point.