The LimbSaver Barrel De-Resonator is designed to dampen out unwanted vibration by shortening the overall settling time of the barrel. The result is improved accuracy with even over the counter factory ammunition. The unit is easily installed by lubricating the barrel with light gun oil and simply sliding the De-Resonator over the barrel. Fits most standard/medium contour barrels. Front sights should be removed prior to attaching unit. Models: Standard or Bull barrel.