Mammut Smart Belay Device LEFTnotruc(Popular belay device for both indoor and sport climbers,500) Dynamically brakes the climber in an accidental fall and locks even at low levels of force exerted by the user In the event of sudden shock, the function corresponds to the reflex movements of the human body Improved geometry of the carabiner opening allows comfortable releasing of the lead climber Suitable for all current HMS carabiners and single ropes from 8.7 to 10.5 mm in diameter