I liked the idea of being able to unscrew a knob to easily fill a tank so I ordered the one from mom and pop store. This is the most frustrating tank I have ever used. It comes with a prepunched cart so the first carto worked great. Easy to refill. The problems came when I had to replace the carto. The endcaps are not solid they are a soft pliable rubber material. They bend when you try to insert them into the tube. I have messed with this thing for 2 days. I have tried the suggestions on the reviews and its a no go. This tank is going in the "cant use" drawer. Going to stick with my cheap dependable smoketech tanks.