Single Spring is a elastic sling system allowing a you to climb leashless with out the fear of loosing your tools. The Single Spring is attached to the harness. The small carabiner is hooked onto the hole on the axe’s head when using it to lean on when walking or through the hole on the spike when holding the shaft in traction. In both cases it is impossible to lose the axe. The system allows the climber to swap hands or tool easily.