This a VERY complete STEC 55X or Fifty Five X system with everything needed to install including trays and harnesses for everything. This is a 28V system that has 200hrs of use in a turboprop aircraft. Removed in 100% working condition for avionics changes to the aircraft only. This system is yellow tagged for easy installation either as a complete system or as needed components with added spares for down the road! VERY cheap for a complete system with tags! All manuals and Installation documents included!