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Mammut Smart 2.0 Review

Not the most versatile option but good for single pitch climbing and those who don't like heavier active assisted braking devices
mammut smart 2.0 belay device review
Credit: Mammut
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Price:  $45 List | $20.23 at Backcountry
Compare prices at 3 resellers
Pros:  Compact and lightweight for an assisted braking device, inexpensive, simple
Cons:  Does not have auto-block function, requires learning new techniques
Manufacturer:   Mammut
By Andy Wellman & Cam McKenzie Ring  ⋅  Feb 21, 2020
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  • Catch and Bite - 30% 6.0
  • Lowering and Rappelling - 30% 6.0
  • Feeding Slack - 20% 7.0
  • Weight and Bulk - 10% 8.0
  • Auto Block - 10% 0.0

Our Verdict

Mammut redesigned the passive locking Smart device for 2018, and our testers were impressed with the result. The Smart 2.0 offers you the security of an assisted braking device at an affordable price. It's also lightweight and compact, but it's not the most versatile option. The 2.0 is for single-strand use only. There is a bit of a learning curve with this device, and Mammut also sells a "Smarter" clip-on attachment to prevent misuse. This device is great for single-pitch climbing uses. We preferred it for lead belaying rather than top-roping. It also felt better with skinnier ropes, so if you're still climbing on 10.2mm lines, you might have a harder time feeding slack with the Smart 2.0.

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mammut smart 2.0 belay device review
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Overall Score Sort Icon
Bottom Line Not the most versatile option but good for single pitch climbing and those who don't like heavier active assisted braking devicesAn excellent value for multi pitch climbing, rappels, and double rope ascentsA match made in rock heaven for skinny ropes and climbers counting weightA lightweight entry level belay device that gives our Best Buy winner a run for the money
Rating Categories Mammut Smart 2.0 Black Diamond ATC G... Petzl Reverso Petzl Verso
Catch and Bite (30%)
Lowering and Rappelling (30%)
Feeding Slack (20%)
Weight and Bulk (10%)
Auto Block (10%)
Specs Mammut Smart 2.0 Black Diamond ATC G... Petzl Reverso Petzl Verso
Style Passive assisted braking Auto-block tube Auto-block tube Tube style
Recommended Rope Diameter 8.7 mm - 10.5 mm 7.7 mm - 11 mm 7.5 mm - 11 mm 7.5 mm - 11 mm
Weight (oz) 2.9 oz 2.8 oz 2.2 oz 2 oz
Double Rope Rap? No Yes Yes Yes
Belay off anchor? No Yes Yes No
Assisted Braking? Yes, passive No No No

Our Analysis and Test Results

The Mammut Smart 2.0 is a "passive" assisted belay device. That means that there are no moving parts inside the Smart that cam or pinch the rope to slow it down. Instead, the rotation of the device against your carabiner is what creates the pinch. This device is rated for use with 8.7 to 10.5mm ropes, and Mammut recommends using their Smart HMS carabiner with this device (it has a safety gate to prevent cross-loading and unscrewing). We didn't have one of those on hand and tested it primarily with a Black Diamond Gridlock carabiner. Note that part of the way these passive lockers work requires a certain diameter on the carabiner that you are using, so you should ideally pair them with the recommended carabiner or with a larger H or HMS type locking carabiners from another manufacturer and not the smaller Type B or Basic locking carabiners.

Know How To Use Your Belay Device
The discussion below is meant to help you make a purchasing decision, and should not be used for actual instruction. Check out the instruction manual made by Mammut here for actual usage. Here is a product video from Mammut, although it provides little in the way of instruction.

Performance Comparison

mammut smart 2.0 belay device review - new for 2018, the smart 2.0 has improved braking function over the...
New for 2018, the Smart 2.0 has improved braking function over the first generation. It also retails for an affordable price.
Credit: Cam McKenzie Ring


We thought the catch and bite on this device was superior to that of the tube style devices.

We always kept our brake hand down when belaying with the Smart, which is the recommended technique. Use of the old-school tube-style belay technique is not recommended (where you bring the brake rope above and parallel with the lead side to take in or give out slack). In fact, studies done on the older Smart show that without the hand in the proper brake position the device alone won't stop the climber (though the drop test video of the 2.0 does show it engaging without a tensioned brake hand). Mammut designed an extra little piece called the Smarter, that attaches to the top of the Smart and prevents the ropes from getting too close. They recommend this attachment for newer belayers who are still learning best practices. We didn't test the additional piece — it seems like a good idea, but it does add cost and looks like something that can easily get lost.

mammut smart 2.0 belay device review - the bite on the smart is secure and created by the device pinching...
The bite on the Smart is secure and created by the device pinching the rope. This takes the pressure off your brake hand a little, though you should always keep it securely around the rope.
Credit: Cam McKenzie Ring

The main advantage to the Smart 2.0 and other passive devices over a traditional "tuber" is that you don't have to hold down so hard on your brake hand when the climber has weighted the rope. This doesn't mean that you can take it off completely, just that the device is pinching the rope enough that you can relax your grip a little. We did try opening our hands slightly in some situations to see if the rope would slide through or not, and it always held tight. That's a little more piece of mind that the device is working, but again you should always maintain control of the brake end.


The Smart 2.0 requires a different method for lowering than most other devices. Since the device is "locked" when the climber weights the rope, loosening your grip should have no effect. There is no lever to pull back on, rather the device itself is the lever. While keeping your brake hand on the rope you puush up on the lever with your other thumb, which changes the orientation and reduces the pinch, and the rope starts to feed through.

We didn't like the lowering on this device as much as we did we its closest competitor, the Black Diamond ATC Pilot. The track on Smart is a little longer than on the Pilot, but the rope didn't always want to stay on it, and it was tiring to have to push up with our thumb so much. It also didn't feel as intuitive as lowering with the Pilot.

mammut smart 2.0 belay device review - to lower a climber with the smart, you are supposed to push your...
To lower a climber with the Smart, you are supposed to push your thumb up against the lever while still maintaining control of the rope with your brake hand (out of the frame below). This method made our hands feel tired and resulted in a jerky lower.
Credit: Cam McKenzie Ring

Mammut doesn't want you to lower by encircling your guide hand around the device and pushing the palm against it to break the pinch, which is how you lower with the Pilot. We did try lowering that way anyway, but the housing on the Smart has metal edges that dig into your palms a little when pushing on it. The Pilot's housing is all plastic and has a better hand feel than this one. If we were looking for a device solely for top roping, we'd go with the Pilot first over this one. However, we like the way the Smart feeds slack better (see below) which is why it edged out the Pilot in our scoring.

mammut smart 2.0 belay device review - the "incorrect" way to lower with a smart. it's hard not to default...
The "incorrect" way to lower with a Smart. It's hard not to default to this position, especially when comparing it to the ATC Pilot because this is how you lower with that device. Instead, Mammut wants you to lift up the end with the thumb of your guide hand. Neither way felt particularly smooth. Be sure to check the instruction manual for proper guidance.
Credit: Cam McKenzie Ring

Feeding Slack

If you've been belaying the same way for 20 years, you may not like this device — and/or you might end up short-roping your partner a bit while you get used to it! Belaying with the Smart 2.0 might take some getting used to, as it's completely different from most tube style devices and most active assisted braking devices. While you can pay out slack slowly as with a tuber, when you want to give a lot of slack you have to disengage the device by pushing upwards on the lever with the thumb of your brake hand (with the rest of your hand still around the rope). This lets you pull up lots of slack with your other hand relatively smoothly.

While not as smooth or intuitive as a tuber at first, once you've become accustomed to the technique it works well. The lever on the Smart is more sensitive to pressure and doesn't require much force to disengage it. We tested this device with a newer 9mm and a "fuzzy" 9.7mm and found that it fed slack out much easier with a skinnier rope. This device is ambidextrous though, so lefties might appreciate its feed even more.

mammut smart 2.0 belay device review - lead belaying with the smart. note how the belayer keeps the rope...
Lead belaying with the Smart. Note how the belayer keeps the rope within the grasp of their brake hand while pushing up with that thumb. That pressure allows you to pull slack out quickly with your guide hand without the device locking up.
Credit: Cam McKenzie Ring


This device weighs a scant 2.9 ounces, which is a significant difference from the heavier assisted braking devices.

If you are looking for something lighter to replace your GriGri with, this could be what you are looking for.

mammut smart 2.0 belay device review - the smart 2.0 (left) and atc pilot (right) have a similar weight and...
The Smart 2.0 (left) and ATC Pilot (right) have a similar weight and size. It will likely be a personal preference whether you prefer one model over the other.
Credit: Cam McKenzie Ring

Auto Block (resistance belaying a second)

We did not test this model for its auto-block resistance as it is not designed for this purpose.


The Smart 2.0 retails for the same price as comparable and similar devices. If you choose to buy the "Smarter" add-on, it will bump up the total a bit. You can purchase it with the Smart HMS carabiner in a package, which is a good value.


Passive assisted braking devices have elicited a lot of "whys?" from people when they spotted us testing them out at the crag. Think of them as a cross between a GriGri and an ATC. If you're partial to tube-style devices but want some extra holding power and security, then the Smart 2.0 is a great choice. If you've always used a GriGri but are open to trying something lighter and less expensive, the Smart also fills that bill.

Andy Wellman & Cam McKenzie Ring

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