Digital Volt and Ampere meter for Mass 24/75 Mass 24/100 and Mass 24/100-3ph in front panel.Professional users will benefit from a front display with GMDSS alarm functions. GMDSS stands for Global Maritime Distress and Safety System an internationally agreed-upon set of safety procedures types of equipment and communication protocols that is a requirement for the SOLAS (Safety Of Life At Sea) convention and uses DSC and satellite communication. Battery voltage and current are displayed on the digital panel.