Man have I got a beef with HysraSence. After having nasal surgery I spent $17 dollars on this bottle of Gentle Spray believing it should last awhile so that is a bargain. To my surprise this bottle lasted a day and a half of use. I said to myself that is impossible a few sprays in each nostrel every few hours and this is gone. So I decided to take the bottle apart to check it out. Wow my eyes opened up as to how consumers can get totally fooled by marketing. I decided to put 100ml of water in this bottle and see how full it should be. (Red line in pic#8) Surprise as you can see the water came out of the bottle as fast as was going in due to *** in bottom as in the pictures This made me more curious as to what is going on. I took the centre out of that black garden hose type tube (pic #5) and started to look at that. That is actually the amount of pressurized fluid you get that is flexible and and the fluid filling that is pressurized so it will make the black tube expand to give the spray. Cannot believe how companies can fool people into thinking they are getting so much more than they actualy get. Thank you HydraSense I will stick to other brands that I know will last awhile and be there when I need it