MBR1645 8 Amp, 45 volt Schottky (low voltage drop) blocking diode. For use where a blocking diode is required or recommended in multiple panel arrays. If you have a charge controller and a single panel or single string of panels, you do not need a blocking diode. Note: The manufacturers rating on this diode is 16 amps, but that is in free air. Mounted in a solar panel junction box, where temperatures can be very high, also reduces the ratings. They are probably safe in many cases up to around 12 amps, but we prefer to allow a safety factor.