Now with external fill access to the OMEGA HydroTanium Reservoir. Its ergonomic design keeps you comfortable for hours. Low infrared reflective [LIRR] buckles, webbing, and materials on the Coyote and Army Universal Camo models provide an edge on the battlefield during night ops. With streamlined features, external fill OMEGA Reservoir, and zippered front access panel, operators ask for it by name.The ThermoBak can also be purchased with our NEW Chem-Bio Reservoir (4.0) which attaches easily to Type M, A, or S Gas Mask Adapters.Adapters sold separately (see Related Products).ThermoBak 3L in 500D available in ABU and Digital Woodland.