An ATC
An ATC from the top
The usual method of rigging an ATC
One method of tying off an ATC
The ATC (Air Traffic Controller) is actually a Black Diamond brand, but the name is often used for the generic tube type belay devices.
They consist of two tubes of metal, through which loops of rope are fed, and the ends of the loops clipped into the carabiner on the harness.
They are designed as a belay device, so are not ideal for abseiling. However, plenty of people use them as they already own one of these for climbing.
They are not ideal for canyoning as they need to be taken off the harness to clip or unclip from the abseil rope.
| Safe | No major issues. |
| Quick release | No |
| In line | Yes, although some twisting of the rope often seems to occur |
| Light weight | Yes |
| Variable speed | No |
| Variable speed during descent | No |
| Easy to lock off | No |
| Rescue use | No |
| Belay use | Yes |
| Heat dissipation | Below average |