Buyer’s Guide to Mechanical Tree Climbing Devices - Part 2: Today’s Most Popular Devices

In part 1, I covered why mechanical tree climbing devices have become such a cornerstone of modern arboriculture and how to think about choosing the right category for your climbing style.

Now it’s time to talk about specific tools.

Time spent in the canopy - pruning, removing, ascending tall trees, and experimenting with multiple tree climbing setups I learned that every mechanical device has its own personality. Some feel familiar right away. Others are quite cheeky. Some demand patience. And some quietly become your daily driver before you even realize it.

Below is a practical overview of today’s most talked about-climbing devices, along with real world pros and cons from a working arborist’s perspective.

Petzl Zig Zag (Plus)

The Mechanical Hitch That Feels Like Home

For many tree climbers, Petzl Zig Zag and/or Petzl Zig Zag Plus is (or was) their first step towards mechanical devices. Petzl did a phenomenal job designing something that mirrors the feel of a traditional hitch while adding consistency and efficiency.

The Zig Zag will have a fixed attachment point and uses a chain-based friction system combined with a pulley which makes tending rope one-handed simple. If you have spent years on a Blake’s hitch or hitch based system, this transition feels natural. No need to adjust friction, simply follow the device specifications for tree climbing rope diameter and standards.

The Zig Zag Plus adds will have a swivel attachment point, which keeps the system correctly oriented, it does not eliminate rope cross.

Pros:

• Extremely intuitive for arborists transitioning from hitch-based systems
• Smooth, predictable descent control
• Durable construction
• Excellent for MRS
• Feel organic in hand compared to more technical devices

Cons:

• Not mid-line attachable, the arborist rope must be threaded through the device
• Less convenient for frequent changeovers
• Requires additional components to climb SRS

Possibly best suited for: Climbers who primarily run MRS, want a mechanical prussic that preserves a classic feel, and for those who don’t need adjustable friction to dial in a device: in other words, simple.

My take: Petzl’s Zig Zag (Plus) is like the mechanical version of comfort food. It’s reliable, smooth, and familiar! It is possibly the smoothest mechanical on the market without the need to dial friction settings in order to dial it in, which means the learning curve is minimal if any.

While the device supports SRS climbing techniques, its compact form is no longer due to the necessary pairing with the Petzl Chicane.

ISC Reflex

A Modern Mechanical Prussic with Mid-Line FreedomThe Reflex feels like ISC looked at a certain device and said, “Mid-line attachable…hold my drink!”

The ISC Reflex is a mechanical tree climbing device that is functional for both MRS and SRS climbing techniques, without the need of adding a friction brake to it (unless the user would like to and for specific techniques, refer to the user manual for details). This mechanical prussic is mid-line attachable.

Pros:

• Mid-line attachable
• Smooth, hitch-like control
• Works well in both MRS and SRS
• High rescue rating
• Replacement parts

Cons:

• Slightly heavier
• Limited replacement parts

Possibly best suited for: Hybrid climbers who bounce between SRS and MRS, want mid-line attachability, and want a device ready for rescues.

My take: If you like the Zig Zag concept but want modern functionality, the ISC Reflex feels like a natural evolution. This device attracted me with its impressive aerial rescue capacity and of course the mid-line attachable feature is nice. One thing I noticed with how friction is applied; it is not as smooth as you would think but still very practical for work. I don’t see myself using this for a work climb event at a tree climbing competition.

I think the detachable swivel is pretty genius! Think back to those weird and awkward positions where the climbing system was out of reach all that was needed was the slightest bit of slack to adjust positioning, yet the device felt like it was a mile away. See where I am heading with this?! The swivel can be left attached onto the bridge therefore eliminating the need for a carabiner and reducing the total length of the climbing system.

Akimbo 2

Adjustable, Mid-Line, and Highly Tunable

The Akimbo 2 gives tree climbers something many devices don’t: on-fly-friction adjustment without tools.

You can quickly tune this device to different ropes, climber weight, and climbing styles quickly, which makes it incredibly adaptable. Add an easy mid-line install, and you’ve got a powerful hybrid device that works well in both SRS and MRS.

There is a learning curve, but once dialed in, it’s impressively versatile.

Pros:

• Mid-line attachable
• Tool-free friction adjustment on the upper and lower arm
• Works in both SRS and MRS
• Highly customizable feel

Cons:

• Takes time to dial in properly
• May be like certain ropes better than others
• No return attachment for an eye splice

Possibly best suited for: Tree climbers who want total control over device behavior and regularly switch systems.

My take: The Akimbo 2 , in my opinion, works better in SRS climbing and Ponytail redirecting is a dream! The Akimbo 2 rewards patience. Spend the necessary time on the ground dialing it in, and it becomes a very capable all-around device.

Rope Runner Vertec

The Ultimate SRS Mechanical

The Rope Runner Vertec is, to me, the final evolution of the Rope Runner Pro; I mean, what else can be done to it. The Vertec addressed many user requests: tool-free friction adjustment (to stay current with competing mechanical tree climbing devices), easier mid-line attachment, and smoother descent across rope types and climber sizes.

It’s designed primarily for SRS in mind but is allowed in MRS configuration as well.

Pros:

• Tool-free friction adjustment located at the Bird
• Mid-line attachable
• Excellent descent control
• Strong SRS performance

Cons:

• Higher cost
• Conversion kit from bollard to pulley sold separately
• No return attachment for an eye splice

Possibly best suited for: SRS-focused climbers who desire adjustability and consistency.

My take: The Rope Runner Vertec is a device that excels if you plan to dedicate it to SRS climbing. Even after being tested and approved for MRS (same as with the Akimbo 2), the setup is sloppy if a Rock Exotica Hydra is not utilized; tending can lead to carabiners cross loading.

The bollard of the Rope Runner Vertec allows for smooth descent. The Aeris Kit does make some difference, which will be noticeable on redirects and tending.

The Vertec is a polished, professional system built for production and competition.

Advanced Rope climbing Technology (A.R.T) Blackbird

Soaring to New Heights

Regrettably, as we have not yet received any stock, I am unable to offer a first-person user description at this time. Nevertheless, I am able to provide comprehensive details and an overview of the Blackbird.

A.R.T.’s Blackbird has the ability to transition between SRS and MRS and maintains a streamline system thanks to the return attachment for the eye splice, it really is an impressively engineered tree climbing device.

Build quality is typical A.R.T.: solid, refined, and clearly designed for professional abuse. It also features replaceable wear parts, which matters when you’re climbing daily.

Pros:

• SRS/MRS compatible
• Mid-line attachable
• Replaceable wear components
• No additional hardware required for SRS
• Approved for rescue with two people on SRS and MRS

Cons:

• Higher price point
• Slightly heavier
• Quick wearing components

The A.R.T Blackbird will have a learning curve.

Final Thoughts

Every device in this lineup is capable of safe, efficient climbing when used correctly. The real difference comes down to:

• Your preferred climbing style
• How often you detach from your arborist rope
• Whether mid-line attachment matters to you
• How much adjustability you want
• Your tolerance for complexity

Mechanical tree climbing devices don’t replace skill, they refine it!

My advice? Try as many as you can when attending tree care conferences. Spend time low and slow practicing. Because at the end of the day, the best device isn’t the most expensive or most popular, it’s the one that fits your workflow and keeps you climbing strong for years to come.