The ILBE was designed during the Law Enforcement and Armed Forces (LEAF) program by Arc'teryx, and later manufactured by Propper. The backpack is made from 725 Denier Cordura material (725 D), with the MARPAT camouflage pattern printed onto it. The pack is also covered with a wide grid of the Pouch Attachment Ladder System (PALS), for the attachment of smaller modular pouches. It includes a main pack, a detachable assault pack. The ILBE can hold up to 120 lb (54 kg) of weight, and has room for both 60mm and 81mm mortar rounds outside the main pack. The assault packs, with their smaller volume and lower weight capacities, are intended for wear in combat, while the larger main packs are intended to carry everything needed by a unit on the march. A set of packs typically consists of a main pack, an assault pack & a removable internal radio compartment. These three items together cost more than $600 when the ILBE system was first fielded, making it the most expensive single soldier pack system used by the US Marine Corps.