Big Boy (aka Big Blue) units use standard-sized high flow vessels that are capable of delivering 16 gallons per minute. They also use larger 4.5" X20" filter cartridges for increased filtration capacity. The LOC/NO option is in the "Normally Open" Position. Big Boy units come with 1.5" FNPT (female nipple pipe thread) Ports for minimized pressure drops. Comes with a 5 micron sediment filter, 10 micron carbon block and UV lamp. These are tough, heavy duty units built to deliver very clean, bacteria-free water.