I found this canteen at a garage sale today. Don't think I've ever seen one like this. It is made of hard OD plastic and measures 7" in diameter by 3-1/2" thick. It has marked on one side "ABCON CORP. 2 QUART JEEPO FREEHOLD, N.J." The canteen appears to have been made during the Vietnam War, but I'm not sure.
https://www.milsurps.com/images/impo...canteen1-1.jpg
https://www.milsurps.com/images/impo...canteen2-1.jpg
https://www.milsurps.com/images/impo...canteen3-1.jpg
https://www.milsurps.com/images/impo...canteen4-1.jpg
https://www.milsurps.com/images/impo...canteen5-1.jpg
https://www.milsurps.com/images/impo...canteen6-1.jpg