The instruments
SoLEXS is the Solar Low Energy X-ray Spectrometer. HEL1OS is the High Energy L1 Orbiting X-ray Spectrometer.
Together they span the soft and hard X-ray range of solar emission.
Complementary views
Soft X-rays describe the thermal response of the corona. Hard X-rays capture the impulsive, non-thermal phase. Flare physics needs both.