Altech Voltage Monitoring Relays offer various features for voltage oversight across different systems. The AMR-AP3U690V2D model is designed for 3-phase systems, while the AMR-EP1M230V1 is for 1-phase systems. These relays provide functionalities like undervoltage detection, window monitoring, and supply voltage alignment. The AMR-EP1F480277V1D is also designed for 3-phase systems, offering monitoring capabilities for undervoltage, phase sequence, phase failure, and asymmetry.