REVERSO®, Versatile, lightweight belay/rappel device, for use with one or two rope strands and ability to belay a second climber from the anchor - Petzl Other
Petzl - Reverso – Dick's Climbing
How to belay the leader with a REVERSO - Belaying techniques - YouTube
PETZL Reverso Climbing Belay Device Versatile, Lightweight Belay/rappel Device, for Use with One or Two Rope Strands and Ability To Belay A Follower From The Anchor | Lazada