Arc'teryx Rho Lightweight Wool Toque
The Arc'teryx Rho Lightweight Wool Toque is the thinnest merino beanie in the lineup at 30 grams. Built from 95% merino wool and 5% elastane, it handles 35°F to 55°F during active use. The four-dart cut sits flush under helmets, and the doubled headband adds targeted ear warmth without thickening the crown. At $45, this costs less than most Arc'teryx toques and packs down to almost nothing in a jacket pocket. Model #: X000005990 (current); earlier versions used Model #13456.
I keep one in my shell for shoulder-season hikes and early-morning trail runs when full winter beanies are overkill. The merino stays warm even when soaked with sweat, which matters on stop-start efforts where you're generating heat on the climb and cooling fast at the summit.
Note: Arc'teryx also produced a Rho LTW Long Toque (Model #9085) at 49g with 95% wool/5% spandex for those who want more coverage.
⚠️ COUNTERFEIT WARNING: Fake Rho Lightweight toques have appeared on resale sites. The dead giveaway is price, fakes show $99 MSRP on the hang tag, but the real version retails for $45. Also check for "ONE SIZE" on the interior tag (real ones come in S-M and L-XL). See our authentication guide before buying secondhand.
95% Merino Wool with Doubled Headband
The 95/5 merino-elastane blend uses New Zealand wool sourced under the Responsible Wool Standard. Merino regulates temperature naturally, staying warm when wet and wicking sweat during high-output efforts. The elastane holds the fit over time, which pure wool toques can't do, they stretch out and bag after a few months of regular wear.
The doubled headband is the standout detail. It adds a second layer of fabric across the forehead and ears without thickening the rest of the toque. That targeted approach keeps the crown thin enough to disappear under a ski helmet while still protecting the areas that lose heat fastest. For a deeper look at how merino compares to synthetic and acrylic options, see the beanie materials guide.
Best for 35°F to 55°F Active Use
The Rho Lightweight works from 35°F to 55°F during moderate-to-high effort. Below 35°F, you'll want something heavier like the Rho Toque in Torrent microfleece, which handles colder temps with better wind protection. Above 55°F, even this thin merino traps too much heat once you're moving.
The sweet spot is spring and fall trail runs, shoulder-season hikes, and cool summer mornings at altitude. I've taken it on four-day September hikes near freezing and it performed perfectly. This is the right weight for those conditions.
How Does the Rho Lightweight Wool Toque Fit?
Arc'teryx offers S/M (up to 57cm) and L/XL (58cm+). The S/M fits snug on my head and fully covers my ears, while the L/XL gives a slightly relaxed feel without slipping. The elastane content means the fit holds after repeated washes instead of slowly loosening the way 100% wool does.
The low-profile cut slides under any ski or climbing helmet without creating pressure points or bunching. It's noticeably thinner under a lid than the Bird Head Toque or any of the polyester options. For detailed fit comparisons, check the beanie sizing guide.
All Rho Lightweight Wool Toque Colorways
Arc'teryx rotates colorways seasonally and has released this toque under different names over the years, including the Rho LTW Beanie and Rho Lightweight Beanie. The Rho LTW Beanie first appeared on arcteryx.com in late 2007, described as a "wool beanie" alongside the Rho Balaclava, Rho LTW Neck Gaitor, Covert Beanie, and Covert Pocket Beanie. Early versions weighed 52g in Black, Merlot, and Woodsmoke. By Fall 2015 (Model #13456), the weight had already dropped to 30g in MAPP Merino Wool with six-dart construction and a one-size-fits-all fit. F15 colorways included Adriatic Blue, Black, Gunmetal, Lime Fizz, and Rosella. Arc'teryx's F15 product page also dual-listed the Rho LTW Beanie under both the mainline Accessories and LEAF Accessories categories, confirming the crossover between civilian and military lines.
A Wayback Machine capture from 2019 shows the Model #13456 still active at CAD $40, listed under the Rho and Lightweight Wool categories with an "All Round" activity tag. That era's colorways included Black, Red Beach, and Iolite. The embroidered bird logo and six-dart construction with double-layered headband remained consistent through this generation.
SS24 colorways included Amarantus (deep magenta), Black, and Daybreak (light blue). Previous seasons added Forage (olive green), Sequoia (rust red), Electra (blue), Eden (deep green), Grey, Lt Chandra (magenta), Macaw (bright blue), Crocodile (tan), Tungsten, and Limelight (yellow-green). The embroidered bird logo sits small on the front, keeping the look minimal compared to logo-heavy models like the Grotto Toque. This model is not present in the FW25 accessories catalog.
Merino Pilling and Longevity
Merino pills faster than synthetics. I've seen light fuzz develop after a season of regular use, mostly where it rubs against my stubble and helmet straps. The fabric itself hasn't thinned, though, and the headband seams remain tight. Hand washing cold and drying flat extends the life considerably, machine washing accelerates pilling.
The Smartwool Merino 250 Cuffed Beanie at $35 is the closest competitor. It uses heavier 250-weight merino for more warmth, but the Rho Lightweight wins on packability and under-helmet fit. The Smartwool also runs small, while the Rho's two-size system gives better options for larger heads.
My Most-Used Beanie from October Through April
This is my most-used beanie from October through April. I stuff it in my shell pocket on every hike and pull it out when wind picks up at elevation. It's the first toque I grab for 40°F morning trail runs. It also comes on overnight backpacking trips because the merino doesn't stink after consecutive days of wear.
I've also slept in it during cold camping nights. The wool doesn't itch against skin the way synthetics can, and the snug fit stays put without riding up while tossing around in a sleeping bag.
Find the Rho Lightweight Wool Toque at Arc'teryx or authorized retailers.