Great tool for a great price. I don't know why anyone would buy the smaller wattage versions when this bigger one is priced the same or cheaper :) Granted, an American outlet cannot provide more than 1500W but this thing creates a lot of impact and maybe they measure the joules of each impact, who knows how it got to 3500Watts! It is super heavy and it tore up a 16 inch concrete beam in the ground very quickly. It took 2 days of my older lighter SDS+ hammer drill to chip the top of the beam (before it overheated and died) and then it took 3 hours with this 3500W tool to destroy the whole thing into chunks the size of tennis balls. The weight makes it less easy to use but of course when dealing with concrete the more weight the better. The oil only went down by a dozen drops in 3 hours of use, the same drops used to lubricate the hammer socket. There is no leak, just some small seepage into the socket there which I am thinking is part of the normal operation. This was an awesome purchase.