Disclaimer: Some of the techniques discussed in this post require advanced knowledge of technical rope systems in a vertical environment. Subtleties and nuances abound. Seek qualified instruction from an AMGA certified guide or experienced mentor. Climbing is inherently dangerous, you do so at your own risk. Affiliate links below support this blog.

For over a year I have caught a few social media posts of highly certified guides belaying their clients non-traditionally with a Progress Capture Device or “PCD”. This technique has crept into the recreational climbers tool kit and for good reason, it has some real real advantages over belaying with a more traditional plaquette (Black Diamond Guide ATC, Petzl Reverso, DMM Pivot) or the common Assisted Braking Devices “ABDs” the Petzl Gri Gri 2, Petzl Gri Gri+, the new Petzl Neox.
Choosing to belay with a PCD should be an informed and conscious decision and I hope this post will give you some of the information you should consider when making that decision. The biggest piece of this puzzle simply comes down to appropriate terrain.
- Terrain– This technique is most suitable of belaying a second in 4th and easy 5th class terrain where the probability of a fall is low and the climber is moving at a higher rate of speed. Basically if the second isn’t moving faster then 1 meter a second (3 feet a second) you likely should belay with a more traditional method like a plaquette or ABD.

- Manage Slack– It is imperative with any “toothed” PCD to have minimal slack in the system as the second is climbing. This should be manageable given the lack of resistance when pulling rope, especially through the Petzl Nano Traxion and Petzl Micro Traxion. All three of the PCDs I link below have technical documentation that indicate a load over 4kN or more will lead to sheath damage. If slack is removed while the second climbs, especially towards the end of the pitch when there is less dynamic rope in the system, it should be easy to avoid a 4kN load on the PCD.

- Have Improvised Rescue Skills– This point is well illustrated by the amount of climbers who use plaquette style devices (Black Diamond Guide ATC, Petzl Reverso, DMM Pivot) but have yet to practice lowering from a loaded device. As mentioned earlier using a PCD to belay a second should be in terrain where a fall or lower is not expected. If either of those two things could be needed I would likely choose a different belay technique, however, unexpected does happen. If you are experienced enough to belay your second with a PCD you should have a solid understanding of release-able load transfers. You should have the skills to swap a loaded PCD with something that would allow a smooth lower (Munter Hitch, LSD, Gri Gri, etc). Making this transition safely and smoothly is something best learned from a qualified guide or instructor. (These skills are covered and practiced in my custom Self Rescue Course, send a message if interested in that curriculum).

A Comparison Look at Three PCDs

| Device | Price | Weight | Rope Diameter |
| Petzl Tibloc | $54.95 | 36 grams | 8 – 11mm* |
| Petzl Nano Traxion | $114.95 | 53 grams | 7 – 11mm* |
| Petzl Micro Traxion | $144.95 | 85 grams | 7 – 11mm* |
* Compatible with the PUR’LINE 6 MM cord only for hauling a pack
* Compatible with the RAD LINE 6 MM cord (more information in the Instructions for Use at http://www.petzl.com)

The Petzl Tibloc is obviously the lightest and most affordable of the three Petzl PCDs I’m comparing here. It is well established as an excellent ultralight weight device for glacier travel, crevasse rescue, and improvised rescue. The addition of the spring loaded mechanism to initiate capture on the newest model of the Petzl Tibloc means it can work as a belay for a second, however, the lack of a pulley means you will feel noticeable more resistance when pulling slack through the system. For this reason alone I think it is worth considering one of the other two options from Petzl, especially now that there is a choice that weights only 16 grams more. Additionally, care needs to be used when installing the Petzl Tibloc to insure the rope passes through the locking carabiner and not just the device!


The Petzl Nano Traxion, while costing twice as much as the Petzl Tibloc, has a lot going for it. First, it incorporates a highly efficient (91%) pulley, which makes pulling in slack, regardless of diameter, quite effortless. At only 53 grams it is the lightest PCD + Pulley I have ever tested. Paired with a Petzl Rocha SL Carabiner and a home tied keeper cord this set up has become the newest edition to the back gear loop on my harness.


The Petzl Micro Traxion is the most expensive and heaviest of these options. The only real advantage of this model is the added mechanism that allows you to lock the cam in the open position so you can use the device as a simple pulley. It’s a pretty small addition to justify the additional cost and weight over the Petzl Nano Traxion.

Compatible Carabiners
My favorite carabiner for all three of these PCDs is the Petzl Rocha SL Carabiner. This small lightweight locking carabiner features a red indicator that aids in visually confirming if it is locked or not and a small hole for attaching a keeper cord to any of these devices. I’m also a fan of the Petzl OK Triact Auto Locking Carabiner and the Petzl OK Ball-Lock Carabiner especially when matched with the Petzl Tibloc.
Deal Alert
Pretty much every product I have linked to in this post is 25% off right now at Backcountry. If you do decide to purchase anything based off the information in this post I really appreciate you using those links. Your support will keep this content coming!
Summary
Climbing techniques continue to evolve with advances in methodology often happening at the highest levels of the sport (certified climbing guides and accredited organizations) and then disseminate to the more general practioners. Belaying with a PCD can lead to efficiency and increased safety in certain climbing situations. Keep in mind the choice should be well informed and consider; terrain, managed slack, and your ability to problem solve unlikely scenarios like needing to transition to an unexpected lower. If you do find yourself in situations where this technique would work for you consider adding the Petzl Nano Traxion and Petzl Rocha SL Carabiner to your kit. After 1400 feet of moderate slab climbing this past weekend with two of my friends my elbows were quite happy I was familiar with this option!
See you in the mountains,
Northeast Alpine Start
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