11581A/11582A/11583C A calibrated set of four fixed coaxial attenuators (3, 6, 10, and 20 dB) is available. Each set includes a calibration report certified traceable to the National Bureau of Standards. The reports included with the 11581A, 11582A, and 11583C indicate the accuracy of measurement and list the attenuation and reflection coefficient at each port of the attenuator. Find us at www.keysight.com Page 8 The set of four attenuators is furnished in a handsome walnut accessory case. In addition to protecting the units when not in use, the case is also a convenient storage place for the attenuators and the calibration reports. Calibration data as described on page 5 is included with rack attenuator set.