Windstopper is a brand of windproof, breathable membrane made by Gore (the maker of Gore-Tex), used to make fabrics — typically fleeces and soft layers — completely block wind while remaining breathable and offering some water resistance. Unlike fully waterproof Gore-Tex, Windstopper prioritizes total windproofing with maximum breathability, making it ideal for active layers in cold, windy, but not-too-wet conditions.
Breathability is a fabric's ability to let water vapor (sweat) pass through it and escape, keeping you dry and comfortable from the inside during activity. Crucial for waterproof-breathable shells and active wear, breathability determines how well a garment vents the moisture you generate, preventing the clammy, sweaty feeling of a non-breathable layer. It's measured by various tests (like MVTR or RET) and always involves a trade-off with waterproofing and warmth.
A waterproof rating measures how well a fabric resists water penetration, most commonly expressed as 'hydrostatic head' in millimeters (mm) — the height of a column of water the fabric can withstand before it leaks. Higher numbers mean more waterproof: roughly 1,500mm is the entry threshold for 'waterproof,' while 10,000–20,000mm+ indicates strong, durable waterproofing for serious conditions. The rating helps compare fabrics, though real-world performance also depends on construction, seams, and DWR.
DWR (Durable Water Repellent) is a coating applied to the outer face fabric of jackets, tents, and other gear that makes water bead up and roll off rather than soaking in. It's essential to how waterproof-breathable garments perform: without it, the face fabric 'wets out' and breathability collapses even though the membrane still blocks rain. DWR wears off with use and washing and must be cleaned and reapplied to keep working.
eVent is a brand of waterproof-breathable membrane, like Gore-Tex, used in rain jackets, shells, and footwear. It's known for its 'direct venting' technology, in which sweat vapor passes straight through the membrane's pores without first needing to build up — giving it a reputation for excellent breathability. eVent keeps rain out while letting moisture escape, and competes with Gore-Tex as a high-performance waterproof-breathable option.
Gore-Tex is a brand of waterproof, breathable membrane used in outdoor jackets, gloves, and footwear. Its microporous membrane has pores far too small for liquid water to pass through but large enough to let water vapor (sweat) escape, keeping rain out while reducing internal condensation. It is the best-known of the waterproof-breathable technologies.
