I carry two 20lb propane tanks on the camper and get frustrated every fall camping season because of not knowing how much propane is left in my tanks. 
The gauges and stickers don't work.  Weighting the bottle is the most actuate way but is alot of work when the bottle are covered and strapped down.
[img width=249 height=241]http://www.rvsupplywarehouse.com/content/product/small/whitecylinder.jpg[/img]

There is a new see thru propane bottle which sense to be the ideal solution.  I've done some research and checked out the reviews.
Pros: Monitors level in winter
Cons: Hard to fit accessories, Opening could be larger

Pros: Easy To Clean, Easy To Use, Improves Grill Function, Saves Time
Cons: None

Pros: Lightweight
Cons: Difficult To Use

Pros: Easy to carry, Monitor propane level
Cons: Different dimensions

Pros: Durable, Good Value, High Quality
Cons: None

Pros: Good Value
Cons: Wondering if it will last
[img width=315 height=231]http://www.litecylinder.com/static/assets/pages/page/image/NewsHero_.jpg[/img]

Does anyone have any experience or has anyone seem them?