Insulated jackets come in a range of different weights, and I own a lot of them. I have light PrimaLoft midlayers that pack down into their own pockets. Ive got burly goose feather parkas that I reserve only for the coldest days. Then theres everything in between, from insulated vests to waterproof down ski jackets and midweight insulated hoodies.

　　Id put the Mammut Sender IN jacket ($260) in a class of its own, though. Not just because the sustainable insulation material is very warm (which it is) but because this 100% recycled jacket is simply denser than all my other puffy jackets. The Sender IN uses a type of insulation Ive never seen or heard of before.

　　The fill inside this puffy, called LOOPINSULATION, is made from scraps of recycled climbing rope.

　　(Photo/Will Brendza) Recycled synthetic insulation is growing in popularity around the outdoor retail space, but LOOPINSULATION is an altogether new take. Its also a novel selling point for Mammut in what is increasingly an oversaturated market.

　　I got my hands on a Sender IN jacket as Colorados weather was starting to get cold. Its been on numerous hikes with me, a late-season camping trip to the desert, dog walks, nights around town, and to the base of ski areas, where it kept me warm while I changed clothes.

　　Through it all, the LOOPINSULATION continued to surprise me. I dont like packing it or carrying it if Im not wearing it. But warmth-wise, this jacket is a winner.

　　In short:Mammut takes the circular economy to the next pitch with the Sender IN hooded jacket. The insulation comprises recycled climbing rope scraps, and the outer material is 100% recycled polyester. Its windproof and water-resistant with a PFC-free DWR coating. It also has a two-way stretch for ease of movement. This is a great jacket for everyday use, though Id be reluctant to take it on any adventure where weight and packability are priorities.

　　Mammut Sender IN Hooded Jacket Check Price at MammutCheck Price at Backcountry

　　(Photo/Mammut) Specs Weight: 696 g Outer material: Recycled polyester Insultion: LOOPINSULATION from recycled rope scraps Fill weight: 330 g Cut: Regular fit Pros Very warm for cold days 100% recycled Insulation made from recycled climbing ropes Stretch makes movement easy Cons Heavier than normal insulation materials Not very packable Left handed zipper Will Brendza Mammut Sender IN Hooded Jacket Review The Mammut Sender IN jacket itself carries a pretty basic design. The hem and cuffs are nonadjustable elastic to seal out cold air. It has two zippered pockets on the front. Raglan sleeves widen the underarm area, allowing greater freedom of movement. The jackets two-way stretch also aids that. It zips high up on the face, and the hood could conceivably fit under a helmet — though it might be a tight squeeze.

　　The first time I wore this jacket, I thought it felt stiff. However, I realized that was just the weight and density of the insulation material. I could move around just fine, and the jacket didnt impede me. It was just bulkier than I had expected.

　　(Photo/Will Brendza) However, off the bat, I could also tell this was a higher-quality stretchy down jacket than some of Mammuts competitors similar products. This is a well-made piece of gear.

　　I dove into testing, leaving the Sender IN hanging by my front door for me to grab whenever I went for a walk, hike, errand, or trip to the ski slopes.

　　Warmth Weather Protection Thermal insulation is the most important quality of any puffy jacket. In this department, the Sender IN scores high marks. I have consistently worn it in 25-35-degree weather with nothing but a T-shirt underneath. If I wear a fleece hoodie or another midlayer under it, I could comfortably brave temps down to 10 degrees — maybe colder.

　　I havent yet worn this jacket under a shell because it cuts wind so well on its own. But if I were in severely windy, wet, and/or cold conditions, I would trust this jacket to be an effective midlayer insulator.

　　(Photo/Will Brendza) The Sender IN came with me to the ski slopes, and I wore it like a changing parka in the lot. As I slipped my comfortable clothes off and changed into ski attire, this jacket kept the cold at bay.

　　When I went on early morning 20-degree walks, the Sender IN balked at the cold and kept me warm. If I were an ice climber or winter rock climber, I wouldnt hesitate to make this jacket my belay jacket.

　　It was too warm when I took it hiking. I ended up shedding the layer and carrying it. Exercising in the Sender IN gets hot fast, even in the cold.

　　Packability I considered taking the Sender IN jacket with me on a ski tour up near Leadville one day. But I changed my mind when I started stuffing it into my pack. This jacket doesnt pack down well. Thats something Mammut notes on its site, giving the Sender IN a 2/6 packability score.

　　A 0-degree down sleeping bag on the left for scale, and the packed Sender IN jacket on the right; (photo/Will Brendza) That was also the reason why I left it in the car when I went backpacking in Utah. I didnt want to carry it and I wasnt even sure I could fit it in my pack.

　　I did wear it the last night when we car camped. Temperatures in the desert dropped to around 30 degrees, and I was more than comfortable. (However, I was also extra cautious around the fire. I know what happens to climbing ropes when theyre exposed to flames, and it isnt pretty.)

　　Weight Ive already mentioned it, but this is a heavy puffy jacket at 24 ounces.

　　Compared to the RAB Nebula Pro ($240), which uses PrimaLoft SilverRise recycled synthetic insulation and recycled fabrics, the Sender IN is 4 ounces heavier. Compared to Patagonias Macro Puffy Hoodie ($400), which uses recycled PlumaFill insulation and recycled fabrics, the Sender IN is 8.5 ounces heavier. And if you look at it next to any of the jackets in GearJunkies guide to the Best Synthetic Insulated Jackets, its by far the heaviest.

　　Again, Mammut is not under any illusions about its own product. On thewebpagefor the Sender IN, Mammut gives it a warmth-to-weight score of 2/6.

　　Zipper Mammut is a European climbing brand, and some of its products have European quirks. Take, for instance, the Sender INs zipper, which is left-handed.

　　(Photo/Will Brendza) I am a right-handed American male. All of my jackets are right-handed zippers. So, naturally, I struggle when the script gets flipped. It isnt a big deal, but its something to note if youre going to spend $260 on a jacket.

　　Mammut Sender IN: Who Is It For?

　　(Photo/Will Brendza) Its pretty darn cool that Mammut has found a way to turn climbing rope scraps into synthetic insulation. We seem to be moving beyond using basic recycled materials to a place where we can shop for products based on what theyre recycled from.

　　Whether its a duffel made from plastic bottles, a jacket made from recycled fabrics, tires built on used tire casings, or the Sender IN jacket insulated with old climbing ropes, there are options.

　　In the case of LOOPINSULATION and the Sender IN, I believe that Mammut has created something both unique and functional. As a jacket, it is warm and comfortable and allows for easy movement. However, the weight and packability problems make it a hard sell for any adventure where those are priorities.

　　Thats not a deal breaker. If you plan on using the Sender IN for belaying people at ice or rock climbs, walking around town in the cold, changing in ski area parking lots, or generally lounging around outside in any temperature under 40 degrees, this jacket is a great option. Its also competitively priced if you look at our list of the Best Synthetic Insulated Jackets. The innovative recycled climbing rope fill is just a cherry on top.

　　Fully Recycled, Supremely Cozy: NEMO Jazz Double Sleeping Bag ReviewWith the NEMO Jazz 30 Double sleeping bag, you can bring bed-like comfort to any campsite you and your partner park at. Read more

　　Check Price at MammutCheck Price at Backcountry Will Brendza