Sizing and Fit

At illumination equipment, we design packs that climb well, ride well, and fit real bodies.

Ski loads differ fundamentally from alpine or hiking loads. Climbing and hiking packs assume your heaviest gear sits near your center of gravity. Ski and snowboard mountaineering breaks that assumption: carrying skis or a board—diagonal, A-frame, side, or vertical—inevitably shifts weight well behind your center of gravity. That shift concentrates pressure on the collarbone, one of the shoulder's most sensitive areas.

Our shoulder straps are shaped around this reality. We position the widest point of the strap directly over the collarbone to spread out that pressure. But width alone isn't the answer—straps too wide in the wrong place dig in and rub, especially on smaller frames. Our straps taper at the neck and under the arm to eliminate pinch points.

To dial in this fit, we offer multiple strap shapes built around the anatomic and performance needs of men and women, plus foam densities and thicknesses tuned for comfort and durability on each product. The result: a pack that moves with you, distributing weight so you can focus on what matters—the first turn off the summit or the slog back to the car after dark.

Our packs come in three torso lengths for men and two for women—each strap ergonomically matched to its torso length. Not sure how to measure your torso? Keep scrolling.

  • Our sizing corresponds to torso length:

    For men:

    Large: 19.5 - 21 in

    Medium 17 - 19 in

    Small: 16 - 17 in

    For Women:

    Medium: 17-19 in

    Small: 15 - 17 in

    We want to be as transparent as possible when it comes to sizing. Sizes outside this range are uncommon among our customer base. We’re not saying you don’t exist. If you fall outside this size range and you want a pack, contact us and let’s talk about how to build you a pack that fits!

  • Torso length is what you would expect: the length of your torso. Or more specifically, the distance between your C7 vertebrae and your iliac crest (the top and most prominent part of your hip bones.) To figure out your torso size, you’ll probably need a friend to help you measure. Stand with your hands on your hips, with your index fingers running level to the floor, along the top of your iliac crest, and your thumbs extending parallel in the opposite direction towards your spine. Ask your partner to measure from the level of your thumbs to the C7 vertebra (the prominent bump at the base of your neck as you slightly lean your head forward.) That number will correspond to the numerical range in the drop down menu on the pack product pages in the web shop.

    Don’t have a friend around? Just want to do things the easy way? Take a pack that you know fits you well and measure from the insertion point of the shoulder strap to the bottom of the hip belt. That number will also correspond to the drop down menu. Please keep in mind that due to various pack/shoulder strap designs, this method may not be perfect, so we recommend the first method when possible, especially if the pack has an adjustable torso length,

    If you are unsure about sizing, always feel free to contact us and we’ll do our best to help you dial in your fit.

  • We build packs to fit a wide range of bodies. However sometimes people fall right on the line between sizes.

    If you’re in between sizes, you can go for the bigger or smaller size depending on what kind of fit you prefer.

    Do you like your pack high and tight with minimal weight on your hips? Go with the smaller size.

    Do you have a narrower than average torso for your height? Go with the smaller size.

    Do you prefer distributing as much weight to your hips as possible? Go with the bigger size.

    Do you tend to hike and ski with multiple thick layers? Go with the bigger size.

    Our shoulder straps are designed to correlate with torso length so focus on finding the right torso length.

  • Unlike pack sizing, choosing pack volume is very much a personal decision, and is based on how you like to ski in the backcountry, and what type of gear you carry.

    When in doubt, we recommend the Luminary 35. It is a pack that won’t weigh you down on fast and light missions, but has enough volume to handle gear-intensive outings like glacier travel or ski alpinism. For those who are extremely dialed with a minimal overnight kit, you can likely get away with using the L35 as a multiday pack.

    The Luminary 27 is the ideal pack for minimalists and free riders. With minimal swing weight and just-enough volume the L27 shines during done-in-a-day fast and light missions, especially when you’ll be managing steep, technical, or exposed terrain with minimal gear. Or you’re teeing up some rowdy lines, and maybe some flips or spins in avalanche terrain.

    The Luminary 45 (launching in 2025), is for multiday trips and guides. With the core features of the Luminary series, the L45 includes volume and features particular to multiday expeditions. Similarly, for guides, the extra volume provides extra space for rescue sleds and shelters, robust first aid and repair kits, “just-in-case” ropes and other tools of the trade.