Gear Slings
Gear Slings are designed to hold a trad rack. Gear slings go over your neck and shoulder making it easier to hold more gear in an organized fashion. Gear slings are optimal for long routes where gear must be constantly transferred from one climber to the other, but many climbers carry them on shorter routes as well. Normally for single pitch climbing the easiest solution is to place your trad rack directly on your harness, which keeps it out of the way and preserves your balance (by keeping it closer to your center of gravity). However, many people prefer gear slings because it's easier to organize your gear on a sling and it makes the gear more accessible.

Depending on the amount of gear you are taking, and how much organization you want to have, there are all kinds of slings available.