Depending on the distance one must travel and the age, condition, and weight of the individual, handled ascenders can mean the difference in reaching a destination with energy to spare or not. Ascenders lock in one direction and can be pushed, nearly friction free, in the other. SherrillTree's handled ascenders attach midline on ropes measuring 8 to 13 mm (5/16-1/2 in. dia) and have a spring-loaded safety latch that must be manually tripped to insert or remove rope. Each is left and right-hand oriented with the latch located thumbside for convenience and safety. Holes provide clip-in positions, depending on the application. All are made of lightweight aluminum, with formed hand holds for comfort. Handled ascenders have small teeth on the cam for traction in the presence of ice and mud and will cause accelerated wear to ropes with heavy use. Petzl's hand ascenders have a slightly curved tooth which is more effective in ice and mud. Right and Left hand.