small enough i can brush properly without a gag reflex but sonic takes getting used to [SEP] oh my goodness the size of the toothbrush head i can actually brush all of my teeth without triggering my gag reflexthat alone should get it five stars butphilips was not kidding about the sonic part that part will take quite a bit of getting used toand while i like that i can use mouthwash in the air flosser instead of limiting myself to water sometimes i prefer a steady stream of liquid over the pulses this thing uses i will still use it on occasion i just will not be getting rid of my waterpik any time soon