CR: 306 是一种通用数字声级计，符合了IEC 61672的全部要求2级。该仪器具有 'F'（快速）的反应，'A'和'C'频率比重。除了提供设施，以容纳最大读数在测量期间发生。
The CR:306 is a general purpose digital sound level meter which meets the full requirements of IEC 61672 to Class 2. The instrument has ‘F’ (Fast) response and both ‘A’ and ‘C’ frequency weightings. In addition facilities are provided to hold the maximum reading occurring during the measurement period.
The CR:306 allows noise levels to be checked quickly and simply, with the large display showing the Sound Level (SPL) with the standard dB(A) frequency weighting. dB(C) Frequency Weighting is also provided.