You're probably safe to accept their offer; these devices are typically shunt-protection types so would not cause any series-current limiting or ground hum. Be aware that there are different models of primary arrestors. Carbon block types are really cheap & will mainly prevent a house from burning down, but that's about it. M.O.V.'s (metal oxide varistors) are very fast & clamp down transients to very low levels, although they're somewhat limited in current capacity for the lower cost models. Gas discharge tubes are the best: more costly, clamp down low, & can handle a lot more current & repetitive hits. I have an industrial grade Joslyn gas discharge primary arrestor across my main service inputs. I've heard it operate a few times when lightning hits closeby; it sounds like the "surge hum current" of a very large motor starting up. One hit was so big that the shunt current draw actually tripped out the main breaker on the utility pole's service disconnect. I still have additional MOV's: one across my dedicated line's outlet, as well as MOV's internal to the Chang Lightspeeds which also serve for AC noise filtration. Of course I recommend a Joslyn as the best level of protection, but anything is better than nothing at all.
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