The Petzl Mobile replaces the popular Petzl Oscillante - it's virtually the same pulley but the sheave is aluminum instead of Nylex - runs on self-lubricating bushes. The aluminum plates on the Petzl Mobile make it very lightweight. Excellent friction hitch tending pulley for one-handed lanyard adjustment - and its also handy for that unexpected hauling of gear into the tree. Swing plates make the Mobile quick and easy to instal even mid-line. The aluminum sheave and side plates offer an excellent strength-to-weight ratio. CE EN 12278/UIAA. 3-year guarantee.