I purchased the symmetric hole version with spring.
Feeding the rope, single or double, is no problem (even with a double 11mm), however old, not-so-flexible ropes are hard to manipulate. For belay, I never had to catch a leader fall. The spring prevents the plate from permanent camming (very useful at rappelling) and has absolutely no "wobbling effect". For rappelling, especially on double rope, it's the best device. You can slip down as a thunderbolt and arrest the rappel at any time with minimum grasp. I've seen serious climbers to use it. However, with the announcement of the Petzl Reverso (of the same prize) its rule
seems to fade.
Ideal for: quick multi-pitch routes, winter conditions, ice.

Similar Products Used:

Petzl Reverso
Black Dee ATC