The lightweight Air Brakes are constructed of an ultra-modern energy-absorbing compound and will reduce recoil energy and noise on any Matrix or Micro model crossbow. Tests show an eight-decibel reduction in noise without a reduction in arrow speed. The kit comes complete with bars, pads, and mounting hardware, installation takes only minutes. Designed to fit MATRIX & MICRO Series crossbows only. PRODUCT #7017 NOTE: The string will need to be removed to install this kit so we advise you also need to purchase a Stringing Aid #2096 Does not fit older EXO series, Twinstrike, or Assassin Extreme crossbow models.