To use the wrench, engage the teeth in the indentations in the nut. Here the tub nut and the drive block are positioned in my vise very much as they would be in the washing machine tub. Strike the arm welded to the pipe with a hammer. The nut is right-hand thread, so strike to make the nut turn counter-clockwise. The nut on my washer loosened almost immediately, even though I had tried several other strategies before with no success.