PROS	CONS
Lightweight and minimalist design	Only two gear loops instead of three to four
Packable for hike-in climbing where every gram counts	Lack of padding for long-climb comfort
Unique sizing system for waist and leg loop ratio	Leg loops are not adjustable, and fit looser in larger sizes
Breathable and light for climbing on hot days	Not our first choice for lead climbing or multi-pitch climbs due to lack of padding and gear loops

When the hardnesses arrived, we were very excited to get them out of the box! We received two sizes: a 2A and a 5A, based on our measurements and the sizing chart. We wanted to test how the harness performed on a smaller female climber and a larger male climber.

The harness comes in a lightweight, sleek bag that is easily packable for nights at the climbing gym or on a camping trip when you plan to get in a quick sport route outdoors.

Out of the bag, to be honest, we were surprised by how thin the loops and straps were, and by the minimalist construction. The lightweight design and thinner loops were very different than the other harnesses we’ve used by competing, established brands. Additionally, there are only two gear loops for quick draws, which at first seemed like not enough for extended, multi-pitch climbs. However, for gym climbing and sports climbing, for which the harness is marketed, the number of gear loops was fine.

We put the harnesses on and adjusted the rear rise elastic. It is a slip/cinch knot design, which we weren’t used to, but we quickly figured it out. The leg loops are not adjustable, so it’s important to refer to the sizing chart when ordering your harness or to try it on at a retail store.

For us, we found the leg loops fit a little large. The climber wearing the smaller harness found that the leg loops were true to the sizing chart; however, there was a lot of room around the thighs in the larger harness.

The harness was very light with minimal resistance on the thighs and allowed for high steps while climbing up the wall, which was a pro. With this wide range of motion, this harness would work well with stemming, crack climbing, overhangs and general climbing. The harness stayed in place without any shifting throughout the climb.

The two gear loops were accessible, but we didn’t need to use them for our gym climbing session. It was really warm in the gym that day, so they noticed that the harness was quite cool compared to the heavier, padded ones. We felt we could go from top rope to bouldering and move around the gym without needing to remove the harness. This would be a good choice for hot-weather climbing.

Lowering: It did the job, but there was discomfort in the groin/inner thigh in the female climber. The male climber didn’t have these issues, but his thighs had more room with a slightly looser leg loop. Personally, we would not choose this harness for all-day climbs suspended from a wall. I wouldn’t want to spend a lot of time with my weight suspended in this harness, but it could be more comfortable for some.

Taking a Fall: When taking a fall, it was comparable to most harnesses in that moment of initial impact. But you can feel the inner-thigh sharpness in the leg loop because it lacks additional padding. Someone softer around the middle might feel that edge at their waist. However, it was perfectly safe, and we felt very confident in its safety performance.

ACTIVITY	PERFORMANCE
Gym Climbing	Excellent
Sport Climbing	Good
Trad Climbing	Fair
Multi-Pitch	Fair
Hike-In Climbing	Excellent

However, we would prefer a harness with more gear loops for quick draws for trad and multi-pitch climbing. For longer climbs where we’d be suspended for most of the day, we’d probably pack our more traditional padded harnesses.

The fit of this harness may not suit all body types. For example, our smaller climber experienced pressure points in the inner thigh, while our larger climber did not. The fixed leg loops reduce adjustability, but some climbers might prefer this streamlined design. It seems that the minimal padding favours weight savings over comfort.

If you’re a trad climber, you might not love the limited gear capacity. It is also more expensive than comparable harnesses on the marketbecause you’re paying for Arc’teryx’s brand, which has a strong reputation for high-quality outdoor gear and apparel.

What we liked most: This harness is really minimalistic and very lightweight. High-stepping and long stretches on the climbing wall were met with virtually no resistance, and it felt streamlined and comfortable. Plus, if you’re climbing on a hot day or in a hot gym, you’ll stay cool in the Lithos SL because it lacks the hot, insulated padding found in other harnesses. If you’re looking for a gym harness you can throw in a backpack or even a large purse, this is it.

What could be improved: For long route climbing or lead climbing, you might find more pressure points and pinching while suspended and certainly on longer falls. What you gain with its lightweight design, we found, was lost in comfort, especially for smaller climbers. In our opinion, it could also use one or two extra gear loops.

The Arc’teryx Lithos SL climbing harness is lightweight and straightforward, perfect for gym climbing and sport climbing. It feels nearly weightless when walking around and on the wall, and is versatile for gym use or short-route climbs. The construction of this harness is simple but supportive, very safe, and the continuous webbing of the leg loops would reduce wear in high-impact areas.

When you first pick it up, this harness feels like there’s not much to it. What you gain in that light design can be lost in comfort, especially for long periods of suspension, harder falls and for smaller climbers who have less “padding” on their thighs and waist.

For those reasons, we give it a solid 7/10 and will gladly keep this harness in our gym bags and hiking packs.