This attenuator is compatible with OP-2 and LM-2 optical sensors. It allows use of the visible (VIS) and infrared (IR) models at 5 watts and 3 watts, respectively. The attenuator threads into the sensor, in place of the light shield, and provides from 1100:1 to 950:1 attenuation. Each attenuator is calibrated for 1000:1 ±5% at 647 nm in our laboratory and supplied with a certificate of calibration. The useful spectral range of the attenuator is 400-1800 nm. The attenuator can be used with power densities as high as 100 MW/cm2.