I believe I ordered this measuring device off Amazon because it had a screw on lid which I thought was a good idea. It has an 8oz marking so I was using that and based on the 32 oz of Bluemax I was thinking I was going to get 4 uses per bottle / 20 gallons of fuel. After the first 2 8oz measurements it was pretty clear to me that I wasn't going to get 4 full 8oz servings. I went to Walmart and bought a small digital kitchen scale and zeroed with my measuring device on it and poured in until it read 8 "fluid" oz whatever that means and it was 9oz on my measuring device. I reached out to Matt (Semi retired Hirth guy) and asked if I was doing something wrong, the attached document is his write up on how he does it. I might try his marking of the bluemax bottle and see how that goes. He said the measuring device I am using is slightly higher mix than 80:1 which is fine by me, rather have a tad more .vs. not enough and damage the engine. I can say the Bluemax oil is pretty thick and not all pours out of my measuring device, even with a small rubber spatula I cannot get it all so I am guessing I am very close to the true 80:1 mark. Figured I would share the info.