Tanks hold 3.1 Gallon (11.5L), are 17" (43cm) long, 11 1/2" (29 cm) wide, have a 2" (5 cm) wide low tunnel and a 3/8 NPT right center petcock opening, as well as rear left and right 1/4 NPT connections. Has universal brackets that makes it easy to mount it to almost any stock or custom frame. These are made from heavy gauge steel.