Where I live in the Pacific Northwest, we average 171 days a year with precipitation. Solid rain gear is extremely important. It also needs to not only be waterproof but hold up to some serious brush-busting. I picked up a set of Stone Glaciers new M5 Hydrashield rain gear (more info here) to put to the test in the rain forests of the Pacific Northwest (PNW.)

Technical Specs

The M5 Series is constructed using a 3-layer Hydrashield laminate that Stone Glacier designed and built themselves specifically with the hunter in mind. The jacket weighs 17.6 ounces in size large, while the pants come in at 15 ounces even. Both jacket and pants have a soft and quiet polyester face fabric with a Tricot backer. Both utilize high-quality waterproof YKK Aquaguard zippers. The Hydrashield laminate boasts an impressive waterproof rating of 31,000mm and an MVTR breathability rating of 27,600g/m2/24hr. So what the heck are these crazy numbers for waterproofness/breathability? Read on!

Hydrostatic Head Testing

When you buy a waterproof garment it usually is rated with some large number of millimeters, but how do they get that value? A hydrostatic head test is performed on the textile to determine its waterproof rating. The fabric is stretched underneath a 1” diameter cylinder, and water is added to the cylinder until it starts to leak through, the height of the water at that point is measured in millimeters and this is the hydrostatic head. A rating of 10,000 mm and under is suitable for applications with light rain, while 15,000 mm and above is meant for heavy rain. The hydrashields rating of 31,000 mm is outstanding. Perfect for my intended use in the rain forests of the PNW.

Moisture Vapor Transmission Rate

Breathability is measured in moisture vapor transmission rate (MVTR). This rating tells us how much water vapor can pass through the textile from the inside to the outside in grams per square meter per day. This is an important number for us as hunters. It tells us how well the garment will “breathe” or transfer the vapor inside our jacket or pants caused by sweat and body heat during high-exertion periods.

Rain gear with an MVTR rating of 10,000 g/m2/24hr and under is suitable for low exertion activities like tree stand hunting or lounging around camp. A rating of 15,000 g/m2/24hr and above is designed for high exertion activities like hunting and mountaineering. The impressive Hydrashield breathability rating of 27,600g/m2/24hr makes it the ideal choice for the backcountry hunter traversing mountainous terrain in inclement weather.

The M5 Jacket folds into its hood making it easily packable.
M5 Jacket

The M5 jacket was designed to be worn with a pack on your back, and it shows. Both pockets are easily accessible above the hip belt. While they may not be as roomy as some other jackets, they are 100% usable and no longer will you have to fight your hip belt to get at something in the bottom of the pocket. A simple solution to an annoying inconvenience while in the field.

Another simple solution Stone Glacier incorporated into this jacket is a rubber-like coating covering the knots of each zipper-pull cord. No longer will you have to worry about the knot coming undone and losing the ability to quickly operate the zipper.


The pit zips on the M5 jacket are key for dumping unwanted heat while trekking up the mountain. They function flawlessly and are designed for easy one-handed operation. The elbow area of the M5 was designed to be a little larger than normal to accommodate lifting your arms to glass and not exposing your wrists to the elements. One of my major pet peeves in rain gear is water running down the sleeve and this helps eliminate that. The cuffs of the M5 jacket Velcro around your wrist providing an adequate seal without the Velcro rubbing your skin as I have experienced with other rain gear.

As with other pieces of Stone Glacier’s apparel lineup, they had the backpack hunter at the forefront of their minds along with its lightweight, the M5 jacket folds into its hood making it easily packable into a lid or pocket of a pack. The articulated hood of the M5 has two shock cords to close any gaps around your face, while also not obscuring your view a welcomed feature while glassing. The tail of the M5 is cut longer than a standard coat to provide protection from the weather while squatting or sitting. More info on the jacket here.

The seams in the knees of the M5 Pant make it extremely flexible.
M5 Pants

The M5 pants are quickly becoming my favorite rain pant. At first glance, they appear to be just your standard rain pant, but if we take a closer look they are really feature-rich. The athletic fit makes them move with you extremely well while hiking and climbing steep hillsides. The knees of the M5 have seams sewn into them making them bend with your leg instead of hindering your movements, it also makes it more comfortable to squat or sit compared to other rain gear on the market.

Stone Glacier Stratum layered zip system allows ventilation all the way to the skin when paired with their other apparel.

Another key feature of the M5 pants is Stone Glaciers’ Stratum layered zipper system. All of Stone Glacier’s technical apparel is designed to work in unison to provide you with comfort and functionality while on the mountain. The Stratum zipper system is a full-length leg zipper that when combined with Stone Glaciers De Havilland pant and Helio bottom, allows you to vent all the way to skin, a unique and well thought-out attribute that works well for dumping that unwanted heat during your trek.

Stone Glacier patent pending Contour Waist System.
Contour Waist System

One of my favorite features of the M5 pant is Stone Glacier’s patent-pending Contour Waist System. This is an easily operated Velcro adjustment located in the crotch of the pant. SG’s goal with the Contour Waist was to eliminate bulk and allow a custom fit waist that reduces hot spots from wearing a tightly cinched pack belt. I found this especially handy when shedding layers. I was quickly and easily able to readjust the Contour Waist for a perfect fit. The Contour Waist gives you up to 2.5 inches of waist adjustment. More than enough to accommodate any layering system you can throw at it. Whether its early or late season, you can custom fit the M5 pants to your needs.

Another welcomed attribute to the M5 pant especially for the brush of the PNW is the reinforced ankle area. I have experienced failures and holes in this high-wear area of the pant in other rain gear. I expect the M5 to last much longer thanks to this improvement in a traditionally vulnerable part of the pant. You can order the M5 pant here.


I have been extremely happy with the performance of the M5 pant and jacket. I put it through some pretty thick brush of the PNW. And, was happy to have no rips, tears, or any sign of wear when I came out. More importantly, it kept me dry. The combination of its excellent MVTR rating, pit zips, and Stratum zip system allowed me to dump excess heat and moisture. That kept me both dry from the outside and inside. The athletic cut made it much more enjoyable to hike in compared to other rain gear I have tried.

My only real complaint is I wish the pockets were just a hair larger. Although they make up for it being 100% usable with a pack on, a little more room would be nice. I think Stone Glacier hit it out of the park with the M5 series.  The two years of development that went into the series is evident. I’m excited to use and abuse this set, and I have no doubt it will last. Order yours here.

You can comment on this article or ask Jake questions here.

Also check out these other clothing reviews.