First things first: The Revo is not a Grigri-style belay device, despite any misconceptions. (An earlier version of the Revo was positioned to be released in 2017, but the device was withheld from the market until May 2018 pending some design tweaks and mass-production and certification issues.) Instead, it functions pretty much like a standard tube-style device, but—here’s the catch (get it, “catch”?)—the Revo has a wheel inside that, once it passes four meters per second, or freefall velocity, automatically engages a cam that drops into a groove in the wheel, locking the wheel up to arrest the rope. In other words, the Revo is a tube-style device with a centrifugal-force-activated backup that engages if you either lower your climber too quickly, bobble the belay, or don’t have your brake hand on when your climber falls (shame on you!). Given the amount of accidents that result from belayer error, the Revo sets out to address some common scenarios, especially ones encountered with less experienced rope-handlers.
We tested the Revo extensively both on fatty gym ropes and slick redpointing cords, at the local rock gyms and local crags, on routes from 10 to 35 meters in length, passing the device back and forth between a handful of us, trading belays and comparing notes. First, the basics: The Revo weighs 285 grams (10 ounces) and works on ropes from 8.5 to 11 millimeters. It’s bidirectional, meaning you can load the rope in either direction, which is great for ambidextrous or left-handed belayers. It’s easy to thread: Simply unlock the face plate with a small, simple lever, and feed the rope all the way around the wheel so that it’s seated in both the entry and exit grooves. (It will still lock as advertised even if you don’t seat the rope in the exit groove—basically a three-quarters thread—but this is not the correct usage.) A meaty, solid device, the Revo clips nicely to a locker, staying oriented toward the climber with little drama or fuss.
The first thing everyone noticed, and a huge selling point, is how easily the Revo pays out slack—better than any device I’ve used, tube-style devices included, with an intuitive, easy feed thanks to the rolling action of the wheel. Even with that fast-climbing or cruxing friend who whips up an armful of cord to make a desperate clip, it rarely seized up. The payout is buttery, making this a perfect device for long and/or difficult redpoints, with lots of clips and where smooth rope action is paramount. I’m thinking of the long pitches on the Project Wall at Rifle or the Motherlode in the Red River Gorge, where you need to be whipping out slack by the armful, repeatedly and often. It also lowers well once you get the hang of it; the best methods we found were to either to keep the guide hand high on the climber side of the rope and the brake hand low by the hip, using the two in tandem to control the descent; or placing both hands low on the braking side. One caveat: Because the device is so frictionless, things did get a little jerky with skinnier/newer ropes; lowering works better with fatter cords.
Now to that backup and locking mechanism. To test, I straight-up took off the brake hand with a climber weighting the rope (hanging or lowering), going against every habit ingrained in me. Sure, it was spooky the first few times, and we put a knot in the rope as a safeguard, but in the end didn’t need it. The Revo without fail locked up when the rope passed the advertised speed, catching the climber within one to four feet—it may have caught sooner in every case, but I likely wasn’t consistent in how quickly I removed my brake hand due to my natural instinct not to do so. That said, because the wheel needs to travel around for the cam to engage in the groove, there may be play in the fall length. While this unpredictability was initially disconcerting, I would not call it a major issue. Again, the lock is a failsafe—your first line of defense is your brake hand—so only with a climber very close to the ground would any inconsistency matter. On a final note, the lock, once engaged, is very easy to disengage—you simply tug down on the rope in the groove and the cam/jaw unlocks.
In terms of catching falls, the Revo works like a tube-style device, letting a little slack slip through organically to give a dynamic catch, which means you don’t need to be that aggressive with the up or forward “soft catch” jump. And, of course, if you let too much slack slip through, it will lock up. To consider, however, is that if you properly catch a fall, the locking mechanism will not engage, meaning if your climber starts rage-batmanning back to their high point or wants to do an extended dogging session, it’s going to be on you, as the belayer, to manage the rope, reeling it in and locking it off in tube-style mode. (One subtle method that works for engaging the locking mechanism is to pull down on the climber side of the rope to release tension, engage the cam/jaw with your index finger, then slowly sit back on the rope to take out the slack—this does take some practice.)
Casting around online, I found rave reviews from parents who loved how the Revo let their kids comfortably give them belays, with the intuitive slack feeding and inbuilt backup. It was also popular for teaching newer belayers at the gym, and certainly does instill good belaying habits by teaching people how to use a tube-style device off the bat—while still getting that key backup you want with a novice belayer. I can see the Revo becoming very useful for redpoint climbers and diehard craggers, and going gangbusters in rock-gym, guiding, and instructional scenarios. It feeds slack like a dream, and the idiot-proof, bomb-proof backup is a mega-bonus. Even if you panic, the Revo will come through, and it’s clear that the design has been carefully tailored to address common belayer failings.