Our original shower head has a button to shut off the water flow, I'm unfamiliar with the Oxygenic and do not doubt it may reduce the flow rate in the shower. Having had both I have wondered about the claim of the tankless uses more water the tank heaters. I do believe that the biggest loss of water occurs while mixing the hot and cold water to the correct temperature. We set the temperature on our tankless to the temperature we desire for the shower and just turn on the hot water so there is no playing with the cold to get the correct temperature. I do notice the quick temperature loss of hot water in the line running to any fixture in the rig and wonder if a little insulation around the line might help, this has been noticed on both the tankless and tank heaters.