In 1988, the Integrated Individual Fighting System (IIFS) was adopted by the Army. The design was based on commercial backpacks modified for military use with the addition of a special fighting vest and a detachable patrol pack. The original focus was to develop a load-carrying system for use in cold weather. However, in the final analysis, the Army selected the new internal frame system as a replacement for the external framed All-purpose Lightweight Individual Carrying Equipment system.

The large field pack with internal frame is used to transport the individual's existence load in all environmental conditions. Even load distribution is achieved through the adjustment features. The patrol pack is used for short missions, and can be attached atop the field pack.

The combat patrol pack was designed for short missions and offers 1200 cubic inches of cargo space in two compartments.

The vest is designed to transport the basic load of 40mm grenade ammunition for the grenadier. It is a one-size-fits-all item constructed of very strong nylon fabric and webbing.

The vest is designed to transport the individual's fighting load. It is a one-size-fits-all item constructed of very strong nylon fabric and webbing.

Military specification MIL-F-44324 covers the IIFS large field pack and combat patrol pack.

Military specification MIL-V-44323 covers a webbing harness load bearing vest to carry ammunition, grenades, canteen and other equipment.

Military specification MIL-V-44362 covers one type and size of nylon duck vest intended for carrying 40-mm grenades.