The MS-5S Zaku I was a mobile suit that was mainly improved in terms of its equipment, and fell between the MS-05 and MS-06 in status. The MS-06 incorporates many components that are common in the MS-05, but its armor and parts were incorporated into the MS-05S before being applied to the MS-06. A new type of shield mounted on the right shoulder was developed, which could protect the machine over a wider area. And for offense, a new type of left shoulder armor was introduced, with spikes installed for increased damage during ramming attacks. In addition to the standard MS machine gun (drum magazine type) and Type A1 MS bazooka, the MS machine gun (belt-fed type) was developed, which had increased ammunition thanks to a feed mechanism mounted on the mobile suit's back. The backpack was substituted with the MS-06's backpack for greater propulsion. Although it was a temporary measure, the MS-05S's comprehensive ability was strengthened, and the MS-05S was sent into the Lunar Attack Force, as the mass production framework for the MS-06 had yet to be created.