Balmar Alternator Protection Module APM12 12V [APM 12] Fish Magnet Cold Weather Ready: Built in internal 1058732105 P20A1S3 Cold Weather Ready: Built in internal heating system provides seamless performance even in freezing conditions without additional equipment It requires a flat section in the hull to be mounted and is excellent for boats traveling at high speeds that want to maintain accurate depth readings The APM can absorb multiple surges of such energy and can absorb surges in excess of 200 amps without failure to continually protect your alternator Balmar has introduced a robust Alternator Protection Module which helps to protect the alternator’s diodes and internal voltage regulator against spikes (clamping up to 60V) and sustained over voltage conditions (beginning around 20V for the 12V version)