Its “semi-containment” as the arrow can still move around inside the rest or fall out of the rest (although… I’d really like to see the video of how that happened!) Essentially, you cannot shoot this rest hanging upside down from a tree branch!
This limb activated rest is spring driven with adjustable spring tension. All metal construction means it is quite robust (no… you can’t drive over it!) and with an extremely simple and straightforward mechanical lever action driving the rest, there is very little that can go wrong.
But can something go wrong? Absolutely… you need to make sure that the string attached to the limb can’t slip (otherwise you may get inconsistencies) and if you bow takes a hard nock on the rest itself, you can break off the aluminum rest arm. But to be fair, thats more or less the same for any rest you are going to pick up.
Its easy for me to recommend this rest.
Its not the fastest dropping or the toughest rest. Its not micro adjustable or removable for travel. But it is solid, and it is accurate, and it is consistent, and it will do the job from a hide, treestand or on the stalk. Put it on, set it up and forget about it.