In binoculars, a body made of magnesium alloy is highly preferred over those made of aluminum alloy, polycarbonate, and any other materials because of its commendable strength-to-weight ratio. It is lightweight yet durable. Binoculars with a magnesium chassis are guaranteed to last longer than other binoculars, all without being too bulky to carry. Check out other binoculars with magnesium bodies in this comprehensive review.