The RED from ISC is a backup device made specifically with rope access in mind. The device is really nice and simple whilst remaining user-friendly and very effective.
ISC have provided a good description-
The RED is a simple, yet highly effective backup device.
The RED's non-aggressive Cams have a positively locking spring, which means that the device is self-parking (rather than self-tailing, like many Rope grabs). This self-parking function is important for Rope Access work techniques as they stipulate that the backup device should be positioned so as to reduce fall factors to a minimum.
The RED makes use of 'Rotational Braking'- the more the device rotates clockwise, the greater the build up of friction, which provides the automatic braking in the event of a fall or sudden pull on the Cows-tail.
To increase the effectiveness of the Rotational Brake in a panic situation (for example, a main-line failure), the RED can be fitted with a 'Popper' tow cord release clip*. For further information on the Popper clip, please download the RED Back-up Device Datasheet.