Curtis Instruments India Private Ltd. Supplies Multi-Voltage Audible Alarm. Curtis Instruments India Private Ltd. Is awarded with ISO 9001:2008 certifications. The Multi-Voltage Audible Alarm is designed to protect people working in close proximity to material handling equipment and other types of mobile plant and vehicles. The Multi-Voltage Audible Alarm is suitable for use on fork trucks, tow tractors, electric vehicles, construction equipment and road vehicles.