The Viper D-Loop Pliers allows you to install a perfect d-loop with precision every time. Stretches the loop on the string so it will not slip or turn. FeaturesNew DesignConvenient and versatile archery toolMaximizes mechanical advantage for tightest possible D-loopsMakes the D-Loop a consistent length each timeSpring keeps the tool openApplies 400lbs of pressure equally on each knotLarger ergonomic handles for improved grip