The MS-06M Zaku Marine Type (aka Marine Hizack) is a submarine combat variant of the MS-06F Zaku II, it was first featured in the original design series Mobile Suit Variations (MSV).
As the One Year War dragged on, Zeon began to design several different variations of its standard mobile suits to excel in specific mission roles. The Zeonic Company created the first amphibious mobile suit, the MS-06M-1 Zaku Marine Type (also called Zaku Mariner), based on the MS-06F Zaku II.
The body was identical, except all of the joints were equipped with waterproof seals, and it mounted hydrojet engines on its backpack, arms, and legs as opposed to standard chemical rocket thrusters. The Zaku Marine Type also carried weaponry better adapted for aquatic combat, such as a SUBROC (SUBmarine ROCket) Gun, two 4-tube 240mm rocket pods, and twin vulcans mounted in the head.