This is a field case for your RC4 or TransX3 decoder box that can be placed trackside by the scoring loop. It protects it from rain, dust, and other weather elements. The field case can be powered with the AC power supply (included), or a 12v battery (not included). A jumper cable for a 12v batter is included, but the battery field case is sold separately (LTM-9003). The RC4 / TranX3 decoder is not included.