This was pulled from a lightly used IonSpec FTICR 9.4T Mass spectrometer. The Energy HI/LO switch an attenuating feature that changes the Maximum transmitted energy available. This switch operates independently from the variable attenuator. The Switch has the following 2 settings: 1) HI -full energy is available from the laser . Variable attenuation is about 30:1 for green and about 20:1 for IR and UV. LED on the front panel display indicates 0-100 across the full Range. 2) LO - Approximately less than 40% of High Energy level . The low level is to be used during the alignment and calibration procedures. For more details and pictures please contact us.