The Mars Science Laboratory (MSL) Radiation Assessment Detector (RAD) Level 1 observational counter data product contains time-tagged instrument housekeeping and observation metadata; rover and solar geometry; quality-filtered and all-quality linear energy transfer (LET) histograms for the A1 and A2 silicon detectors with associated LET bin energies; fast and slow hardware trigger counts for RAD detector channels; and hardware event match and read counters. The RAD instrument is described in detail by Hassler et al. (2012).