Price includes timer, transformer, DLFC, and top filter screen.The NBP piston stops untreated water passing through the valve during the regeneration process.There is a choice between the 1600 or 1710 model - if you are not sure which model you require measure the outside diameter of the brine uptake pipe (the pipe from your brine tank to valve head) - if it is 3/8" it is a 1600 head or if it is 1/2" it is a 1710 head. click here for data sheet