Type 1 : Aluminium 55% and Zinc 45%. This material is little Expesive but give very good heat reflection and rust prevention.
Type 2 : Aluminium 45% and Zinc 55%. This material is Cheaper then Type 1. Heat reflection is 9.5% less then Type 1 & Rust prevention is 12.5% less. But is better Hot Dip Galvanize steel. Rust 1.8 times and Heat Reflection 6.8 times.