Review (5/5): Press and HOLD for on/off,  and tap button to change modes.
At first I thought it didn't work, but it works like my bike flasher, not like other flossers. Press 'on' button for 2 seconds to turn on/off and tap the button to cycle through the modes. It remembers the mode it was in when turned off too, like my bike flasher. Doesn't hold a lot of water but very easy to refill. Can't comment on battery life since I just got it. Perfect for travel since the nozzle fits inside and it collapses to 6 inches. Takes very little space on bathroom sink. My gums have started to receed and dentist suggested the oral irrigator to clean out food debris. Like this model a lot and I've used several. Just remember to hold the button down 2 seconds to turn on.