Light-weight Mont Bell rainwear is fully waterproof and highly breathable. The lightness of the jackets and pants means that they take up less room in the pack and are more comfortable to wear. Despite being light, Mont Bell rainwear is durable because of the fabric used. Indeed, if you are interested in light-weight shellwear, we would argue that it is critical to understand how waterproof materials are constructed. A jacket material ideally comprises three layers – a waterproof membrane sandwiched between an outer nylon layer and an inner protective layer. Manufacturers often reduce the weight of rainwear by replacing the inner layer with a light transparent coating, which greatly reduces the durability of the jacket (i.e., the jacket wears out from the inside). Such jackets are called 2.5-layer jackets. 2.5-layer jackets do have their place and are fine to use as long as you don't often carry medium-weight or heavy packs.
The Mont Bell jackets and pants featured on this page are made of 3-layer fabric, yet they are as light as (or lighter than) less-durable 2.5-layer jackets. This is largely because the outer (face) layer of the fabric is Ballistic nylon. Ballistic is 150% more abrasion resistant and 200% stronger (tear strength) than ordinary nylon because it has been heated and stretched, which aligns the nylon molecules. Hence Mont Bell rainwear can be made very light (by essentially using less nylon) without sacrificing durability.