MammutBionic 8 Belay Device

The Terminator of belay devices.

For a scant 2.4 ounces, the Mammut Bionic 8 Belay Device lets you belay or rappel with any diameter rope, including twin and half rope setups. Mammut built this classic, simple device using hot-forged I-Beam technology that gives it an impressive strength-to-weight ratio.

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  • Q & A

Like it

    Using a figure eight makes me feel pretty good. I pretty much got it to stop beating on my atc and for rappelling when I multi-pitch with the grigri. Super light and smooth. Feels a bit weird with different diameter ropes but it could just be me

    Small but mighty ... smooth rappels!

    • Familiarity: I've used it several times

    I was quite surprised when I received this figure 8. All the images on make it look larger than it really is. I was expecting it to be about 6" or so and heavy. But, it's only 4.75" in length and very light. I pictured it with the BD Rocklock carabiner and the Mammut Bionic Mythos HMS Carabiner. This 8 is small and mighty, that's probably why they call it bionic. I've rappelled with it using a double/single strand 9mm rope and it works flawlessly every time. Clean, smooth rappels and it doesn't seem to twist the rope like other 8's potentially do. Great buy!

    Small but mighty ... smooth rappels!

    Eights are…. GRRR--8

    • Familiarity: I've used it several times

    Very light piece of equipment. The bionic 8 puts on a great fashion show, as its a very sexy looking rap device. Works just like the other 8's I've used, no issues here.

    Eights are…. GRRR--8


      This is a great figure 8 device, at first i was tripping when I felt how light it was compared to my black diamond figure 8, but it hasn't snapped on me yet, and it actually has the exact same strength to weight ratio as my black diamond...


      Loving the bionic line

        What can i say i've bought the carabiners and the figure 8 in the bionic line that mammut has because they are functional and look good at the same time. Pretty light and does what you'd expect from a figure 8. notice one thing when using it while rappelling, that it provides more braking than a regular figure 8, i'm guessing from its squarish shape as compared to the more round ones from every other company.

        Light, strong, durable!

        • Familiarity: I've used it several times

        What more do you need out of your 8?!?! Nuff said.

        Basic and functional

        • Familiarity: I've used it several times

        This figure-8 is nice and light, without sacrificing strength and safety. I can slow/stop myself effectively, even at 205lbs. I've only had it one season, so I can't speak of durability yet. Like all things that work on friction, inspect regularly and retire it when you notice a groove wearing into it. Unless you're out playing every day, that should take quite some time.

        My advice is to only use a fig-8 as a rappel device and never as a belay device, except for emergencies. Use an ATC or higher-end device for belaying.

        does anyone know the dimensions of this...

        does anyone know the dimensions of this 8?

        At the widest part the bionic is 3" across, and the length is 4-11/16

        definatly a must

          This pick up was kind of a splurge, but its definatly worth its wieght in gold as they say. Its put me ahead of more than a few storms when i needed a quick and fast route off the rock. havent used it much as an actual belay, but definatly an awesome hasty repell. And, with a quick flip of the rope ive found that i can set comfortably on the rope just hanging as long as i need to get those breath taking shots i find time to time.

          Does any one know the strength on this 8?...

          Does any one know the strength on this 8? Shows nothing on Mammut's website.

          Best Answer

          22 kN along the main axis.