The cold-retention efficiency and long life of this mobile, lightweight dry ice chest is based on the low "K" factor of 0.19. The 2" thick walls of expanded polystyrene insulation used all around are molded in one seamless piece. Since this insulation is non-deteriorating, vapor-proof, waterproof, and non-settling, the temperature protecting performance of the chest remains constant throughout its long life. Weight of the entire unit is only 40 lbs. Enclosing the molded foam insulation core are protective hermetically sealed shells, inside and outside, of tough, leather-grained Royalite (ABS industrial grade plastic) as used for luggage cases and refrigerated truck interiors. Royalite is washable, scuff-proof, rustproof and corrosion-proof, and is U.S.D.A. approved. Color: Laboratory grey. All latches are cadmium and zinc plated. Two spring-loaded, zinc plated lay-down handles are optional. Hinged lid included "snap-open" supports that keep the lid upright, freeing both hands for work procedures. 5 cu. ft. dry ice storage chest keeps 215 lbs. of dry ice for use over a 15-day period. 2.8 cu. ft. model holds 155 lbs. of dry ice for use over a 9-day period.