Battle Armor (called Saiyan Battle Armor by the Earthlings before the Namek Saga) is standard-issue combat attire throughout the Planet Trade Organization. This is a paper model. They are made of an unknown material, which is said to be stretchy, yet durable (Vegeta once remarked "one size fits all"). Even Vegeta as a Great Ape was able to wear his armor without having any size issues. They are known to shatter when dealt enough damage, showing that they are indeed hard and solid.