Rope bags like the name indicates are designed to carry your climbing rope. These bags ill generally have a tard included that is either attached to the bag or can be removed. The tard usually has indications on its edges as to where the beginning and end of the rope can be attached to avoid a knot.
There are some different designs out there but all in all these bags all quiet similar to each other. If you still feel like you need some advice, feel free to come down to the shop or give us a call!