The shower head replaced the "sock" I believe as time went by. All my older trucks have a sock, which basically the pick up tube runs into the end of what for lack of a better word looks like a sock made to fit a duck. The sock is a pourous screen and does little more than some course filtering. Once the fuel level drops below the "heel" of the sock where the pickup tube is, your done. The "shower head" as pictured above is more lick a suction cup that presses against the floor of the trank. Fuel is drawn in through the little notches on the sides. With the sock design, the fuel return spits right on the sock, essentially blasting it clean with regurgitated fuel. The shower head however, can clog more easily, but it will in fact get more fuel out of the tank than the sock will. I had to drop my tank on the 02' Excursion because the shower head got clogged. This happened because I idled the truck while I was filling it with a very low tank. This washed all the sediment that was in the bottom of the tank right over to where the showerhead was due to the fuel draw. If the truck had been off, the sediment would have remained dispursed and it wouldn't have clogged that time. So the leason I learned there was to never let the tank get that low, and to not refill with the engine running if it is.