WTF is a Thread?

I'm planning a dolomites trip and trying to figure out what gear to bring. Several times I've seen mention of bringing 'threads' as a protection suggestion for your rack. From prior euro limestone trips I'm generally familiar with the concept: a hole in the rock between two pockets that can be connected together via a piece of cord or such. However, I'm not sure I know what they mean in the context of a rack - I've seen routes with fixed threads that have a single strand of cord tied in a loop directly through the thread (IE no hitch), but that doesn't seem feasible to carry or set up mid-climb one-handed. 

I assume the rack version is generally going to be a pre-tied loop that is hitched to the thread, but are people bringing slings made of cord, or just using nylon/dyneema slings to hitch the threads (which I'd be worried would snag and might be harder to feed through given their floppiness)? Do people use a nut tool to facilitate feeding the loop through the thread like they do on those knot-pro crags in the Czech republic? This isn't really something you run into in the states and my previous European limestone experience has all been sport/DWS.

Thanks,

Matt

They use aramid cord for the slings, because the rock edges are quite sharp. That's all!

Standard is lengths of aramid cord as mentioned above which is quite stiff so easier to poke through then an overhand in the tails, clip and climb on. Aramid is favoured as the small holes tend to be very sharp inside, the option in other areas like Elbe sandstone are normal cord with a foot or so of coat hanger wire pushed inside to make threading easier.

There are plenty of opportunities for threads in US rock if you're looking for them; I find useful ones periodically.  Short of specialized applications requiring a length of unknotted cord, I think the best and most generally useful set-up is to have some of the Edelrid aramid slings, at least one over-the-shoulder length and one double-length, and more if a lot of threading opportunities are anticipated.   These slings are much easier to thread through holes and constrictions (and deformed piton eyes) than dyneema runners, and are more resistant to abrasion and cutting. That makes them better for slinging spikes and chockstones as well, and, at the end of the day, they are ordinary runners if needed.  Since they are loops, you just clip the two ends after threading; no one-handed knot-tying gymastics required. Of course, you won't be able to thread small holes or constrictions that will only take a single strand.  I don't know how critical that might be in some particular cases, but my possibly misguided inclination would be to just go with the slings, which will be useful everywhere you climb, unless Elbe sandstone is on the tick list.