Materials

Big Agnes stuffed the Fire Tower Belay jacket with RDS-certified (Responsible Down Standard) 700-fill power DownTek, helping it sustain loft when introduced to moisture from body heat and exterior elements. The down performance benefits greatly from the jacket’s Insotect Flow vertical baffle construction. The exterior shell is an ultralight nylon ripstop that offered decent protection against moisture when precipitation was consistent, but light. It’s not a jacket for consistently wet conditions.
The nylon interior is as equally lightweight as the exterior, putting the wearer that much closer to the very lofty, body-wrapping down.

Weatherproofness

This is the jacket for cold, dry days. It performed well with minimalist base- and mid-layers at around 20ºF, but would wet-out quickly when temperature swings resulted in rain instead of snow during a shoulder-season hike near Lake Tahoe. The elastic cuffs and beefy adjustable hood helped keep the cold out, but the jacket’s shorter waistline means its drawcords tighten around the hips, which move consistently, and thus, create the need to frequently readjust if wearing it while active.

Temperature Control

The Fire Tower Belay is a top-of-line performer when it comes to general warmth. The vertically-opposed Insotect Flow system was perfected for sleeping bags to subject more of the body to continuous insulation that is uninterrupted by baffle stitches, or cold spots, helping the 700-fill power down perform above its pay grade. The elastic cuffs, 1-inch+ wide protective flap behind the main zipper, and the enveloping adjustable hood combined to ensure body heat stayed trapped against the core, while the two-way zipper provided options to help prevent overheating.

Fit/Comfort

No other winter insulated jacket tested felt as close to wearing a sleeping bag as the Fire Tower Belay. It’s exceptionally comfortable and wearable, but always noticeable because of its girth and overall volume. This is a true “puffy.”

The medium gently hugged a 5’9’’, 170 lb. tester, but wasn’t restricting or in any way limiting, even with a synthetic mid-layer under it and a backpack over it. It could stand to be somewhat longer, an issue one tester noticed when testing vertical movement. The drawcords at the hem only has a knot of elastic cord available for adjustment, with the housings sewn into the hem, making adjustment very difficult.

Features

The Big Agnes Fire Tower Belay has a two-way zipper, helmet-compatible adjustable hood, and two internal mesh pockets, good for a flask and liner gloves. The vertical, exterior chest pocket is deep enough for snacks, or a smartphone, and like the primary zipper, uses a lightweight, plastic Vislon zipper by YKK.

The included stuff sack collapses the jacket to the size of a basketball; but if pressured, the jacket will accommodate tight corners in gear duffels and backpacks. The weight of our Medium sized sample was verified at 1.5 pounds.

The hood swaddles the head in a down-filled cushion of comfort and can be drawn tight enough to close in above the chin via two internal drawcords. The hood is certainly not flattering when secured, but what it lacks in visual grace it makes up for in warmth.

The elastic cuffs stretched a bit during testing, while the drawcords at the waist didn’t quite keep the coat in place. However, it’s designed primarily as a stationary insulator, thus it’s “belay” classification.