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Rain Wear Guide

Having a comfortable piece of rain wear is imperative for enjoying the outdoors


When clothing gets wet, either from rain or condensation from sweat, it's not only uncomfortable but also a very serious issue, sapping the body of its warmth and strength, a dangerous condition better known as "hypothermia." This is why Montbell uses GORE-TEX® FABRICS and Montbell's proprietory DRY-TEC™ fabric in our rainwear. Using these two materials, we developed a wide range of products that not only allow you to comfortably enjoy the outdoors, but have the ability to protect you from the elements and move moisture outside of the garment.

The world's most waterproof/breathable membrane. GORE-TEX® fabrics are perfect for highly aerobic sports that require the ultimate in waterproof / breathable technology. Available in 3-layer and 2.5-layer and 2-layer constructions.
The membrane has a over 50,000mm waterproofness rating and 35,000~44,000g/㎡ ·24 hrs breathability rating. (JIS L-1099 B-1 method)

Gore-Tex Infinium™ fabrics with WATER RESISTANCE fabrics provide lightweight warmth by combining total windproofness, maximum breathability and durable protection from rain showers. Protects your body's warmth and provides comfort from the chilling effects of wind and rain. Prevents overheating and perspiration build-up by allowing moisture vapor to easily escape. The membrane has a over 30,000mm waterproofness rating and 43,000g/㎡ ·24 hrs breathability rating. (JIS L-1099 B-1 method)

Montbell's originally developed waterproof/breathable membrane. DRY-TEC™ is a non-porous polyurethane treated fabric.
The membrane has a over 20,000mm waterproofness rating and 8,000~20,000g/㎡ ·24 hrs breathability rating. (JIS L-1099 B-1 method)

Denier

Denier is the weight of a 9,000m long thread, and in practical terms it is a good equivalent of thickness. A thread of 1-denier would weigh 1 gram. The higher the denier the thicker the thread becomes and in turn has stronger abrasion and tear resistance. Thicker threads are commonly used for reinforcing areas that are exposed to friction, like edge guards. On the other hand, materials that are made with thinner denier threads feel smoother and are better suited towards clothing.

3-layer, 2.5-layer, and 2-layer products. What's the difference?

Waterproof fabrics all share a common trait of being made with a waterproof membrane. Since the membrane is delicate and easily damaged, it is usually laminated to layers of fabric for protection. For example, a 3-layer fabric is made by laminating a membrane to an outer and inner layer of fabric. This sandwich of outer fabric, membrane, and inner fabric give the materials its 3-layer name. As its name would suggest, a 2-layer fabric is made by laminating the membrane to only an outer fabric. Although lightweight, this comes with a tradeoff of exposing the membrane. Montbell products made with 2-layer fabrics receive a special coating on the inside of the product or are lined with mesh or taffeta to protect the membrane. On the other hand, 2.5-layer fabric is made by laminating the membrane to an outer layer of fabric and then the membrane receives a special dot-print coating that protects the membrane and prevents it from coming into contact with skin or your clothing. It's not quite a 2-layer and isn't quite a 3-layer, hence the 2.5.

Waterproofing - Stopping water from getting in -

Waterproofing is a measure of the ability to resist pressure from external moisture trying to permeate into a material. This property can be described with a numerical value that measures "water pressure resistance." Water pressure resistance is measured by placing a column of water on the outside layer of a material and applying pressure until water begins to seep through, at which point the height of the water is measured in millimeters.

Breathability - Allowing trapped moisture to escape -

Is a high level of water resistance the only feature your hard shell needs? Vinyl raincoats certainly have a very high degree of water resistance, but they cannot release heat or water vapor that builds up inside. Similar to windows on a cold winter morning, water vapor can cool and condense into water droplets on the inside of your jacket. So even if your hard shell is able to protect you from external moisture, if it can’t release water vapor, you can still get wet from internal condensation.

Breathability refers to a material's ability to release built up water vapor. GoreTex Fabrics and other membranes make this possible by keeping water from getting in and allowing water vapor to get out. Membranes can do this because liquid water molecules (rain) are larger than vapor molecules (evaporated sweat), which allows vapor molecules to escape through the membrane's microscopic openings. (left figure, excluding certain materials.)

Montbell's Rain shell jackets are tested by JIS L-1099 B-1 Method when measuring breathability.

Although the performance of a hard shell's waterproof breathable membrane won't degrade over time, DWR treatments will degrade. Therefore, maintaining a garment's DWR treatment is essential maintenance for the overall performance of your hard shell.

The more your garment is worn, the more its DWR treatment is affected by dirt and friction. When a garment's DWR treatment becomes worn down, water is able to spread out over the fabric's surface, saturating it and blocking the membrane's pores. With the pores blocked, water vapor trapped inside is unable to escape. A hard shell with no water repellency can become saturated with water, becoming heavy and rob the body of its heat due to water's high thermal conductivity.

When you start to notice that rain no longer beads off of your hard shell and the outer fabric is instead absorbing water, please see our maintenance and care page for more information on retreating your hard shell.