Finally found a fair price for a surge protector. Bought a Surge Guard Mo. 34750, 50 amp with LED. First night at Topsail Hill SP FL. used for first time. At approx. 0115 hrs I heard a very loud series of "bangs". My pillow is directly above electrical storage bin . I thought this must be the magnetic contactor in the SG. My 120 volt digital plug in meter inside the MH indicated the voltage was fluctuating from 121 to 126, well within the safety range, although the 126 seemed a little high. I called the park maint. electrician to check the pedestal and he said everything was fine, proberly a branch rubbing a wire. He also said that these surge protectors are very sensitive and he thought they were a waste of $. OK. I called factory tech and he said the SG was doing what it is suppossed to do and the noise I heard was indeed the Contactor and if I did not have a SP I proberly might never have heard a thing. Last night at approx. 0215 hrs, same thing, Went on and off for until 0515. This time my 120 volt digital monitor alarm went off but I could get to it fast enough to get a reading and the voltage was steady at 126 volts. The "banging is very loud,even scares the yorky. Is all of this normal? I am getting a little nervous. Your thoughts please.