This specification covers one type of lightweight field and mobile shelter designed for transport by cargo truck, fixed or rotary winged aircraft, rail, and ship, as shelter, electrical equipment S-280/G. Core, adhesive, and sealer materials used in the construction of this item shall be in accordance with the density, compressive strength, shear strength, flammability, and water absorption requirements. Shock mounts shall be subjected to hardness, resilience, and depression-deflection tests to check for compliance with specified requirements. Construction properties shall comply with the cleaning, arc or resistance welding, lamination (impact resistance), vapor seal, interchangeability, riveting, finishing, marking, shelter gross weight, service integrity, and tightness preconditioning specifications. Environmental service conditions such as moisture resistance, rapid temperature changes, and thermal differential including thermal deformation and heat transfer shall be met. The shelter shall also conform to the requirements for transportability whether in rail or air transport, capability to withstand flat and rotational drops and simulated towing, lifting and towing eye casting hardness, and static door and roof access steps vertical loads for structural integrity. Tightness tests shall be conducted as well to verify shielding from air, door latch torque, light, electromagnetic interference, water, and fording.