I've run 100 watts through them for long periods with no trouble. Ya never seem to get the factory spec sheet with these things when you buy them used. Does anyone know what the factory power feed-thru rating is on these things? Note for fun: If anyone needs or wants a good outboard pre-amp, you can hardly beat these Range Boost models from CPI. Ultra low noise amps. They are both gain amps and attenuators (variable knob) and they significantly increase received signals with little to no discernible increase in noise. High reliability, I've never heard anyone complain about them or see one break down or go bad.