Excalibur Micro Crossbow String - 26in - Constructed of BCY DynaFlight 97 material, Excalibur Crossbow’s Micro / DualFire String reduces creep while increasing speed. They also feature a proprietary center serving which significantly increases string life. BCY DynaFlight 97 material Reduces creep Increases speed For Excalibur Micro Crossbows