In our testing, we found that these fuel cans just don't leak. We've laid them on their sides, flipped them upside down, and even filled them at sea level and them driven to the mountains without a single drop lost. In fact, we had one can actually belch as it relieved the pressure difference from the altitude gain on our mountain trip. After testing the Wedco Jerry cans from Backcountry USA, we've given away all our lod blitz-style U.S. fuel cans. From now on, just like with the British soldiers in the North Africa campaign, it's Jerry cans or no cans for us.