The Metolius rope hook is in an odd category of climbing gear of “optional yet occasionally very handy”. It’s inexpensive ($15), lightweight (2.4 ounces), and does a great job managing your rope. In spite of this, it's an underappreciated bit of gear, so let’s give it a little love. (And, made in Bend Oregon USA, gotta like that!)
Are you going to carry this on a two pitch sport climbing route or a long remote alpine climb where you’re counting every gram? Probably not.
Might you take it on a longer multi pitch route, or a big wall climb? Perhaps yes. Especially the big wall.
If you are swapping leads, then the top of the rope is perfectly stacked for the new leader. If you’re leading in blocks (where the same person takes several pitches in a row) you can grab the entire coil and rotate it so the bottom ends up on the top, ready for the previous leader to head out.
It’s pretty simple. Clip the small sewn loop onto your anchor and pass butterfly coils through the large open “C” shape, which is stiff enough to hold the rope coils even while it's open.
The hook looks fairly small, but the capacity is bigger than you might think. Here’s a 60 meter 10 mm thick rope, neatly done up (rope tail tucked in at the top).
Here’s the rope hook kept open, as you might see at a belay when you are adding loops with every 3-4 meters of rope you take in. Note that the U-shaped bottom part is stiff enough to hold the shape and the weight of the rope, even when the middle buckle is unclipped.