Speaker cable's. I know it's not considered a tweak now but in 1972 it was, friends and family scoffed and laughed at the high quality, thick cable that had no terminated ends just bare wire. There wasn't much of an improvement in sound quality but it was inexpensive and that was important at that time. Later on, a few year's after CD players came along, putting Black Diamond cones under and removing them from the player stopped everyone in their track's, audiophile or not. I still bevel cut and green pen the edges of the little silver devil's.