Digital DC Voltmemter- 0 - 50VDCMonitor marine/land based power distribution & generating systems (ABYC E-11.11.3.2.) AC voltmeter and AC ammeter are true RMS (ABYC E-11.11.3.2.3.) Surface mount with only two 5/32" diameter holes Window mount in standard 2.5" analog meter cutout (2.90" W X 1.28" H) Three digit LED display (Frequency meters are two digits) Reversed Polarity Protected Splashproof front Includes pigtails, mounting hardware, & instructions