A handheld shower head threads onto the existing shower arm -- the same connection as a fixed head. No plumber, no drilling, no wall modification. The kit includes a diverter mount that holds the handheld at fixed-head height when you are not holding it, plus a flexible hose (usually 60-72 inches). You get the convenience of a fixed head for normal showering and a handheld for rinsing kids, pets, cleaning the tub, and reaching spots a fixed head cannot. The entire install takes 10 minutes with no tools beyond your hands and a roll of Teflon tape.