Explainer · Pertex Shield vs eVent · 8 min

Pertex Shield vs eVent: Mid-Tier Shell Fabrics Compared

A plain-language breakdown of Pertex Shield vs eVent: weight, breathability, durability, and packability for mid-tier waterproof shells.

Pertex Shield vs eVent: Mid-Tier Shell Fabrics Compared

Two membrane systems have long shown up in mid-tier ultralight and techwear-adjacent shells: Pertex Shield and eVent. Neither is Gore-Tex. Neither is cheap single-layer coated nylon. They occupy a middle band where weight, breathability, and price trade off in ways that matter on the trail.

The two are no longer equally easy to find. Pertex Shield runs through a wide range of current shells. OutdoorGearLab’s May 2026 test of 18 rain jackets included a Pertex Shield model and no eVent model. eVent itself has changed: the products it has added most recently use PFAS-free membranes rather than the ePTFE that made its name.

This explainer defines both technologies as they are sold today, traces how they differ in measurable terms, and maps which conditions favor each.

What These Fabrics Actually Are

Pertex Shield comes from Pertex, a British fabric brand dating to 1979 and now owned by Mitsui & Co. Pertex describes Shield as a system of tightly woven face fabric, membrane and optional backer, built in 2-layer, 2.5-layer or 3-layer form. Its membrane is either non-porous, passing water vapour by molecular diffusion at a rate Pertex says rises with the wearer’s output, or hydrophobic and microporous, with holes far smaller than a water droplet.

Two related fabrics carry the name. Shield Pro uses an engineered microporous membrane built for durability. Shield Air is an electrospun nanofibre web with an open network of pores. Pertex says many waterproof-breathable membranes have near-zero air permeability, while Shield Air lets air through and still resists wind. Pertex does not name its membrane polymers. Yamatomichi, which builds with Shield Air and Shield Pro, describes both as hydrophobic polyurethane.

eVent is made by eVent Fabrics, which says it was founded in 1999. Its reputation was built on an expanded polytetrafluoroethylene (ePTFE) membrane, the polymer family of classic Gore-Tex. In 2013 GE, then its manufacturer, described the membrane as air permeable, venting body heat and moisture through millions of tiny pores in one step. eVent called this Direct Venting. It still lists the technology as eVent Waterproof, “with air permeable Direct venting technology”, but its current pages do not name the polymer.

Alongside it, eVent now offers:

  • alpineST, for extreme conditions: a “PFAS-free membrane” with a C0 DWR.
  • stormST: a plant-based, PFAS-free membrane, also with a C0 DWR.
  • Protective: a chemical-resistant laminate for military, police and fire use, not labelled PFAS-free.
  • stormburstLT (light rain and snow) and windstormST (a windproof softshell), both PFAS-free and both outside the waterproof category.

Gear made with eVent Waterproof still appears on eVent’s site, but every product added there since September 2025 uses one of the newer fabrics. eVent describes alpineST as a “non-PTFE laminate” and stormST as plant-based and ePTFE-free, but does not name either membrane’s polymer.

Breathability

Breathability in waterproof laminates is commonly reported as Moisture Vapor Transmission Rate (MVTR), in grams of water vapor per square meter per 24 hours (g/m²/24h). ISO 11092, the “sweating guarded hotplate” method, reports water-vapour resistance (RET) instead, where lower is better. ASTM E96 is a family of cup methods. The Japanese listing cited below uses JIS L 1099, and the Korean one names only a JIS standard. Numbers from different test standards are not directly comparable.

Neither fabric maker publishes breathability figures on its fabric pages. Pertex says “standard vapour rate (MVTR) tests do not capture Pertex Shield Air’s full in-use comfort benefit”, because Shield Air also moves warm, moist air through the fabric by convection. Garment brands fill part of the gap. Rab lists an MVTR of 20,000 g/m²/24h on its Shield jackets without naming the test method. Yamatomichi lists catalog figures for its Shield Air fabric of 10,000 g/m²/day under JIS L 1099 A-1 and 40,000 under JIS L 1099 B-1: one fabric, two methods, a fourfold gap. Garment listings on eVent’s own gear pages vary. A 2-layer stormST insulated jacket from Sierra Designs, sold in Korea, quotes 17,000 g/m²/24h to a JIS standard. HLINC gives its 3-layer stormST golf jacket a “20,000/20,000 waterproof and breathability rating”, with no units or method.

Air permeability is the other variable. Shield Air and eVent Waterproof are both sold as air permeable. Yamatomichi lists 0.4 cc/cm²/s of airflow for its Shield Air fabric and under 0.1 for its Shield Pro fabric (JIS L 1096 A), and in its own bubble test, standard Pertex Shield passed no air. eVent calls alpineST and stormST breathable, not air permeable.

Waterproofness

Both fabric families are sold as fully waterproof. Rab rates its Shield jackets at 20,000 mm. Yamatomichi’s catalog figures are 15,000 mm or more for Shield Pro and 10,000 mm or more for Shield Air. eVent’s technology pages give no rating. Listings on its gear pages quote 8,000 mm for the Sierra Designs jacket, 20,000 for HLINC’s and 35,000 mm for Nexarina’s alpineST Avani Snow Pant. In every case the face fabric, construction and seam sealing matter as much as the membrane.

Pertex says regular washing removes the dirt and oils that degrade membrane and DWR. Both makers advise a technical cleaner and a low tumble dry.

Both systems rely on a Durable Water Repellent (DWR) finish on the face fabric to prevent wetting-out, which reduces breathability regardless of membrane type. eVent finishes alpineST and stormST with a C0 DWR, which it describes as water repellency without harmful fluorochemicals. With Pertex fabrics the garment brand chooses: Rab specifies a fluorocarbon-free DWR, while Yamatomichi lists a C6 DWR, a short-chain fluorinated finish, on its 2026 UL All-weather Jacket.

Weight and Packability

This is where Pertex Shield competes seriously, because the range is wide. Rab’s current US men’s waterproof jackets show it (weights for size M):

  • Phantom: 7D 2.5-layer Shield (51 g/m²), 116.5 g
  • Firewall Alpine: 20D 3-layer Shield (90 g/m²), 316 g
  • Downpour: 50D 2.5-layer Shield (122 g/m²), 377 g
  • Firewall: 40D 3-layer Shield (148 g/m²), 495.5 g

Yamatomichi’s 2026 UL All-weather Jacket, which combines Shield Air (58 g/m²) with Shield Pro (68 g/m²), weighs 184 g in size M.

eVent is harder to place. It publishes no fabric weights for alpineST or stormST, and the waterproof jackets it has featured since mid-2025 are hardshells, insulated and snow jackets, and golf wear, not featherweight running shells.

If minimum weight and packability are the primary design goals, Pertex Shield has the broader current selection.

Durability

Neither maker publishes abrasion or wash-cycle test data, so the comparison rests on construction and claims.

Pertex’s answer for hard use is Shield Pro. For Shield and Shield Air it also offers Diamond Fuse face yarns for snag and abrasion resistance. Pertex notes that nanofibre membranes typically decline quickly over successive washes, and says its lamination keeps Shield Air durably waterproof. Yamatomichi reports a different limit after years of field testing: as Shield Air’s DWR wore off, the fabric became more likely to wet out in heavy rain. Its 2026 jacket puts Shield Pro where rain hits hardest and keeps Shield Air under the arms and across the back.

eVent says alpineST holds high levels of waterproofness and breathability “through dozens of washes”. The old argument that eVent’s ePTFE base ages more gracefully than a PU membrane does not carry over to alpineST or stormST, which are not ePTFE.

Price

The four Rab Shield jackets above list in the US at $140 (Downpour), $180 (Firewall), $225 (Phantom) and $280 (Firewall Alpine).

Two US-sold eVent shells sit above that range. Born Primitive’s Mission FLEX Rain Jacket 2.0, a 3-layer stormST shell, is $329. Big Rock Candy Mountaineering’s alpineST Dawn Wall Jacket is $398. The waterproof jackets eVent has added to its own site since September 2025 link to Korean stores instead: Kolon Sport, Zerogram and Sierra Designs’ Korean site.

Use-Case Summary

Pertex Shield wins when: minimum packable weight is the priority, or the buyer wants a wide choice of current garments with published weights, ratings and US prices. Shield Air is built for high-intensity activity where air-permeable venting helps, and Shield Pro for hard, all-day use.

eVent wins when: a plant-based membrane matters. stormST is built on one, and eVent labels both alpineST and stormST PFAS-free at the fabric level. PFAS-free gear alone no longer separates the two. Pertex still marks its 2025 target of PFAS-free production as in progress, but Rab declares no intentionally added PFAS in the Shield jackets listed above, membrane included.

Neither fabric is universally superior. The choice follows from the specific activity pattern and the specific garment, not from brand reputation.

Sources

All checked October 2026.

Affiliate monetization is currently inactive. This explainer contains no affiliate links and was written solely as a technical reference.