2. TYPE - I
Metal construction, typically steel
Affordable due to low production costs
Manufacturing tools & techniques available worldwide
Heaviest of all
3. TYPE - II
Constituent material is aluminium or steel
Cost 50% more than Type I
Weight is up to 40% less
4. TYPE - III
Aluminium liner, carbon fibre composite
Weigh around 0.3-0.45 kg/L
Cost thrice that of Type I & II
5. TYPE - IV
Fully composite construction with hybrid glass fibre or carbon fibre
Weigh almost equal to that of Type III
Cost more than Type I & II, nearly twice or even thrice.