A belay device for use in alpine terrain, based on the tube principle. As well as securing a lead climber, the very light Wall Alpine Belay also allows one or two second climbers to be independently belayed in an autolocking mode from the fixed point. The optimized geometry also allows comfortable belaying as well as reliable blocking in the event of a fall by the second climber, the blocking action can be released again using a sling and the large eyelet on the device. The V-shaped grooves allow the controlled holding of lead falls, even at low levels of manual force. Suitable for twin, half and single ropes from 7.5 to 10.5 mm in diameter.