MITAS Tubes – Heavy Duty and Ultra Heavy Duty Top quality MITAS Heavy Duty and ULTRA Heavy Duty Inner tubes. Heavy Duty : 2mm thickness Ultra Heavy Duty: 4mm thickness Both are fitted with straight necked valves The ultimate protection against punctures if you are still want to run Tubes. 2mm- for all Offroad applications (Adventure riding and low pressure Offroad Racing) 4mm- For medium/high pressure Offroad and Ultimate Adventure riding protection.