The Improved Load Bearing System (ILBE) backpack was designed by Arc’teryx’s Law Enforcement and Armed Forces (LEAF) program specifically for use by the United States Marine Corps. It was created as a replacement for the ALICE and MOLLE systems and based on needs identified during combat situations that arose during the initial involvements in Iraq. The ILBE system is comprised of three main parts, the Assault Pack, the Hydration System, and the Main Pack.
The Main Pack on the ILBE system, also referred to as the ILBE rucksack, was designed to be the main load bearing portion of the backpack. It’s standalone capacity is 4,500 cubic inches. When combined with a supplemental Assault Pack containing an additional 1,500 cubic inches of storage space, the backpack has a capacity of 6,000 cubic inches and up to 120 pounds. The Main Pack itself is made of Cordura 725 fabric and is imprinted with a standard MARPAT (MARine PATtern) on it’s external surfaces. Since the PALS grids were universal in design, the variety of possible attachments was seemingly endless which allowed for servicemen to customize their ILBE Main Packs to suit their individual needs as well as the specific needs of their current mission.
The Main Pack is fitted on the exterior with a Pouch Attachment Ladder System (PALS) grid which allows various smaller items to be attached such as knife sheaths, flashlights, holsters, and ammunition pouches. One unique feature of the ILBE Main Pack that was not present in either the ALICE or MOLLE systems was the ability to carry both 60mm and 81mm mortar rounds external to the pack. This was one of the key requirements given to Arc’terx when the Marines were laying out the specifications for the ILBE system. This allowed easier access to the most commonly used mortar rounds during combat situations.
There are three main configurations for the ILBE system, the Assault Configuration, the Approach March Load, and the Existence Load. All of these aside from the Assault Configuration utilize the Main Pack component. Since the Assault Configuration requires the greatest amount of mobility while maintaining the lightest configuration possible, the heavier Main Pack is not included. Since both the Approach March Load and the Existence Load require soldiers to be able to go for extended periods of time with the supplies they are carrying, the Main Pack is a key component.
When combined with the Assault Pack and the Hydration System, the Main Pack creates a complete ILBE system that serves as the current pack of choice for the USMC today.