Tuber (Tubular belay device)
Tubular belay devices are the most commonly used belay devices during training of advanced climbing and rescue techniques, multipitching and management of twin/double ropes. In some countries/clubs, they have been replaced by assisted tubular belay devices for single-pitch training. They are prohibited in some gyms due to alleged security concerns (for details, see the security concerns section).
Belaying risks
Belaying from the harness
Slack taking
Slack feeding
General risks
Always hold/control the break strand at least with one hand and keep the break strand downwards unless giving or taking the slack. Keep your hand at least a few centimeters from the belay device to avoid pinching of the skin. Do not lift your hand too high (above the device) while giving the slack. One of the commonly seen bad habit is keeping the hand raised for a prolonged time during belaying.

Always hold the break strand downwards unless feeding/taking the rope 
Feed or take the rope from the front of the device 
Not holding the break strand can result in fatal injuries 
Holding the break hand too close to the tuber leads to a risk of pinching the skin of the break hand index finger. 
Do not lift the break hand unnecessary high during the break strand manipulation. 
Do not leave the hand in the upper position if not taking or giving the slack.
Belaying at the anchor
Belaying the second climber
Belaying the lead climber

While belaying from the anchor, redirect the rope in a way that it points upwards even in a case of a fall. Usually an unlocked D-shaped carabiner is used. 
This redirection can be also in some cases built by a quickdraw placed in the second bolt of the anchor if the carabiner is short and the bolt is placed high enough. 
Once the lead climber makes two secure running protections on the route, the redirection is removed.
Belaying from harness at the anchor
During belay from harness at the anchor point redirects the rope through the anchor till the first two pieces of the running protection are placed.
Anchor-belay risks
Belaying at the anchor brings additional risks on top of the general risks. Unlike during belay at a ground level, during anchor belay, climber can get below the tuber level during a fall. If the climber would fall before the first running protection is placed, the tuber would not block as both the break strand and the live strand would be pointed the same direction as illustrated below.
Abseiling
TODO (redirect to technique page)
Tuber as an ascender
TODO
Security concerns
TODO














