I got a lot of weird looks from the Boston TSA personnel when they pulled my green Metolius Rock Rings out of my carry-on. The woman inspecting my backpack simply looked at me with her head cocked and eyebrows squeezed together in confusion. She then beckoned her middle-aged boss over so that I could explain to both of them that the hard plastic holds were for rock climbing training and that they’d been too heavy to remain in my 52-pound checked bag. I was going to Berlin for the summer and had to have something to simultaneously train finger strength and endurance pull-ups with. After promising not to hang them from anything in the airport, TSA let me put my rock rings back in my backpack and leave to find my gate—I’m very happy they did.

When it comes to portable training, rock rings are my go-to. Together they cost $29.95, weight about four pounds, and take up about as much space as my climbing shoes. They also have convenient built-in ropes so that you can hang them from a variety of sturdy and preferably bar-shaped items, including but not limited to: pull-up bars, tree limbs, monkey bars, and hotel stairwell pipes.

Their biggest downside is that the holds—a jug, four- and three-finger edges, and a two-finger pocket—are limited compared to a hangboard. However, sacrificing hold variety is better than bringing nothing when you’re traveling and have limited space and hanging options: Many hotels and hostels don’t have the standard size doorframe required to hang a pull-up-bar-mounted hangboard, and who wants to drag a pull-up bar and hangboard around Europe anyway? That said, I wouldn’t recommend buying rock rings instead of a hangboard if you’re using them as your main home training device. Rock rings are convenient for sneaking in a little strength training when you’re on a non-climbing family vacation, business trip, or want to stay strong between climbing designations while on the road, but, alone, they aren’t necessarily the best device for skipping a few grades or training anything besides edges or good pockets.

Roughness-wise, rock rings are similar in gritty texture to other plastic Metolius hangboards and therefore have decent grip while potentially wearing down your skin a little if used for a long session (not their forte). The bigger skin problem, especially for those, like myself, with smaller fingers, is jug rash. For me, all of the holds are pretty good, as I can easily fit three fingers into the “two-finger pocket,” and the rails are decently deep—for me more than a pad—which is necessary to compensate for their free-hanging quality. However, if you’re an intermediate climber just looking for a quick (30 minutes or less) way to help maintain finger and arm strength, rock rings will do the job without wrecking your skin.

If you only have 15 minutes, you can warm up and then do this 10-minute Metolius Rock Ring workout. Have more time? Do the Metolius workout two or three times in a row to really get pumped. You can also do endurance pull-ups—three to 10 pull-ups every minute for 10 to 30 minutes depending on your strength and time limits—to simultaneously train power-endurance and finger strength. For a climbing-specific core workout, use your rings for L-sits, knee raises, front levers, and other hanging abs exercises. Check out this YouTube video for more ideas to mix things up. Intermediate climbers should aim for doing two pull-up/lock-off days and one or two hanging abs days each week they’re away and not climbing. Beginners, especially those who have never used a hangboard and/or don’t routinely send above V3, should start with two sessions each week and stick to the larger holds to avoid finger injuries.

For me, the best thing about traveling with rock rings is that it’s usually easy to find somewhere to hang them. For example, I’m currently living in Berlin on a summer study abroad program (hence the TSA incident—but that does prove you can stash them in your carry-on), and have been hanging my rock rings in a neighborhood playground (see photo above) for 20-minute sessions. It’s incredibly easy and also fun when I have a pack of five-year-olds around me asking to take turns hanging during my rest time each minute.

Staying strong while you travel doesn’t have to be hard, and, if packing your rock rings is enough to get you to do a few pull-ups and lock-offs while you’re away, then why not invest in a pair? While they’re not the most comprehensive training device, they will make you feel better about your time away from rock and keep you from becoming a complete couch potato.