How the Gregory Zulu 65's ventilated mesh back panel trades a little load padding for airflow, and who should pick it over the Baltoro instead.
By Marcus Hale, Lead Pack Research Editor · Published September 14, 2026, 6:03 PM ET · Updated September 29, 2026, 6:16 PM ET
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In plain English
The Zulu 65 is a big backpack for trips of several days, designed for people who get hot and sweaty. The 65 means it holds about 65 liters, enough for a tent, sleeping bag, food and clothes.
Its back is a tight mesh net stretched across a curved frame, like a hammock stood on its end. Your back rests on the net, and the bag sits a little way behind it. Air can flow through that space, so your shirt stays drier than it would against a solid foam pad.
The trade-off is small but real. Because the load sits a little farther from your body, it can feel slightly less steady with very heavy weight. For warm-weather trips with a moderate load, a cooler back is often worth that small cost.
The Gregory Zulu 65 is designed for multi-day hikers who want a well-ventilated carry more than maximum load-hauling padding, using a trampoline-style mesh back panel that holds the pack body off the back to let air move through the gap. It belongs to Gregory's Zulu/Jade family, the ventilated counterpart to the heavier-duty Baltoro/Deva line, which comes in several sizes, including the 65-liter size reviewed here.
That ventilated design is the defining difference from Gregory's heavier-duty lines: the Zulu suspends the pack slightly away from the back on a tensioned mesh, similar in concept to ventilated back panels used on daypacks but scaled up and reinforced to support a loaded multi-day pack. The trade-off is a small amount of load stability compared to a fully padded, structured back panel, in exchange for meaningfully less heat and sweat build-up on a warm or humid trail.
How does the Zulu 65 fit and carry weight?
The Zulu 65 uses the same core fit approach as other Gregory multi-day packs: an adjustable or size-specific torso length combined with a hipbelt available in more than one size, so frame length and hip circumference can each be dialed in rather than forcing a compromise. As with any Gregory suspension pack, the hipbelt should sit centered over the iliac crest once loaded, since that's what determines whether the load rides on the hips or drags on the shoulders and lower back.
Because the ventilated mesh back panel holds the pack slightly away from the body, weight can feel marginally further from the hiker's center of gravity than on a closer-fitting pack, which is why Gregory generally positions the Zulu for moderate to moderately heavy loads rather than the very heaviest expedition-style packing lists. For most three-season backpacking trips within the pack's rated range, that distinction is minor in practice and the airflow benefit outweighs the small stability trade-off.
What are the Zulu 65's key features?
The Zulu 65 carries a similar overall feature set to the Baltoro, adapted around its ventilated back panel:
Trampoline-style mesh back panel for airflow between pack and back
Top-loading main compartment, often with a front-panel access option depending on the specific version
External attachment points for trekking poles and a sleeping pad
Adjustable torso length paired with a swappable hipbelt size
Hydration-sleeve compatibility inside the main compartment
Exterior pockets sized for quick-access items like a map, snacks, or a water filter
Who should consider the Zulu 65?
The Zulu 65 suits multi-day hikers in warm or humid climates, or anyone who runs hot on the trail and finds a fully padded back panel uncomfortable over a long day, while still wanting Gregory's adjustable-fit suspension system rather than a simpler, non-adjustable pack. It's also a reasonable middle-ground choice for hikers who aren't sure yet whether they'll consistently carry heavier loads and want a pack that handles moderate weight comfortably in a range of conditions.
Hikers whose pack weight consistently runs heavy, or who hike primarily in cold conditions where a bit less airflow isn't a downside, are often better matched to the more structured Baltoro instead. As with any Gregory comparison, trying both back-panel styles loaded, if possible, is the most reliable way to confirm which trade-off suits a given hiker's build and typical trip conditions, since the difference is felt most clearly under a real pack weight rather than an empty demo model on a store shelf.
Frequently Asked Questions
The Zulu uses a ventilated, trampoline-style mesh back panel that holds the pack slightly off the back for airflow, while the Baltoro uses Gregory's FreeFloat A3 suspension with an AirCushion back panel, positioned for heavier loads. Both share Gregory's adjustable torso and hipbelt fit system across the range.
Yes. The ventilated mesh back panel is the Zulu's main advantage over Gregory's padded packs, making it a common choice for multi-day trips in warm or humid conditions where reducing sweat build-up matters more than squeezing out maximum load padding.
The design is simple in principle. REI describes suspended, or tension-mesh, back panels as holding the packbag a few inches off the back to reduce sweat.1 Deuter, which says it introduced its Aircomfort suspended-mesh system in 1984, describes it as a ventilated system with a gap between mesh and back, held in shape by a lightweight, flexible spring steel frame.2,5 The frame has to be bowed to hold that gap open, so the mesh, not a foam pad, is what your back touches.
Gregory, founded in 1977 by Wayne Gregory, describes its design philosophy as packs that should be worn, not carried.6 The Zulu's job is to keep that fit while letting air through. Sizing works as on other Gregory packs, by torso length from C7 to the iliac crest, and Gregory says it sizes identically across men's, women's and unisex packs.7 Some guides give a 30 to 65 liter family range that is not confirmed by a source in this site's library, so check Gregory's current lineup.
The cost of the gap, and how to reduce it
This page notes that weight can feel slightly farther from your center of gravity on a mesh-backed pack. Load research explains why that matters. A review of soldier load carriage found that keeping the load's center of mass as close as possible to the body's gives the lowest energy cost.3 US Army doctrine says packing heavier items higher and closer to the body can cut marching energy cost by as much as 25% compared with low, away-from-body placement,8 an extreme comparison but the same direction of effect.
Packing claws much of it back. The Appalachian Mountain Club advises placing dense items about two-thirds up the main compartment, centered and against the back, and cinching the compression straps once packed.9 With the heaviest things pressed toward the mesh side, the gap costs less.
What a ventilated back can and can't do in the heat
A cooler back is about comfort; it doesn't change how much water your body loses. The CDC Yellow Book says sweat rates can reach about a liter per hour,4 and Grand Canyon National Park says hikers in heat can lose one to two quarts of water per hour.10 The CDC suggests doing outdoor activity during the coolest parts of the day when heat risk is high.11
Drinking plans need care in both directions. The CDC Yellow Book says drinking to relieve thirst helps prevent hyponatremia, or low blood sodium, and calls the idea that you can't drink too much outdated advice.4 Grand Canyon's rangers advise eating salty snacks to balance water intake in hot weather.10 Heat stroke signs include confusion, slurred speech and a body temperature above 103°F; the National Weather Service calls it a severe medical emergency that needs 911 or a hospital immediately.12
