The Karo features a groove on the side that lets you lock the rope in place so that if your climber wants to rest in the middle of a route, you can take a break too.
The tubik: a special case
Want to learn how to rappel? The Tubik is a good option if you’re learning to climb with a double rope.
Keep in mind, however, that the Tubik is not equipped with a belay station anchor ring, so it can’t be used to belay a second climber from a belay station. You would need a supplementary belay plate.
The atc pilot
For an even more secure belay, the ATC Pilot offers reinforced braking while maintaining smooth rope payout.