Hi momtoCory,
I'm on oxygen 24/7, and at home I use a concentrator. When I want to go out, I have oxygen cylinders, with a little oxygen conserving device that "puffs" out air every time I take a breath. I find these cylinders actually more convenient than the strollers I had to use when I went out on passes from the hospital, the devices with liquid O2 in them. I found those to be really heavy and cumbersome. The cylinders are only about 5 lbs and they fit easily into a medium-sized bag or purse. I'm on 4 L/minute, and with the conserver it takes me about 3 hours to get through one. If I'm going out for longer than that I usually bring an extra cylinder, and I always keep one in the car.