Daily Duty, Carrying capacity or strength 40 to 50 kg's re-usable one or twice ideal when normal handling Medium Duty, Carrying capacity or strength 50 to 60 kg's re-usable four to five times ideal for rough use Heavy Duty, Carrying capacity or strength 60 to 70 kg's re-usable many times ideal for rough useLaminated bags are for water or moisture proofing the packaged materials under normal conditions Un-laminated bags are woven bags useful to store and and transport dry material (which has little or no effect from moisture)