OTB SACK Pouch Over The Beach Operations are some of the most challenging and miserable operations that service members must endure. Spiritus Systems is proud to bring a suite of products that directly result in improved load carriage and soldier survival during sea-borne operations. The OTB product line is built with a mesh material, which allows for quick drainage of water and sea-borne debris such as sand. OTB products will dry faster after exiting the water and will drain water more efficiently as well. The mesh also makes the products simple to clean using fresh water after conducting operations in salt environments. The Sub Abdominal Carrying Kit or "SACK" i Mfg: Spiritus Systems