iO HVAC Controls iO-Twin Universal Twinning Kit 549i and has a low battery

and has a low battery indicator

Lead jacks:  2 banana plug jacks for testing open/close switch status (continuity between terminals)

Punches a 1 11/32” hole

Waterproof Base: 3mm Injection Molded Polypropylene

iO HVAC Controls iO-Twin Universal Twinning Kit 549i and has a low batteryiO HVAC Controls iO Twin Universal Twinning Kit The twinning kit is designed to allow a single thermostat to control two separate HVAC units. It can also be expanded to control a total of four HVAC units. The twinning kit can be used on common or separate ducted systems with single stage, multi stage and heat pump equipment. Only standard 18 gauge thermostat wire is required. Thermostats and HVAC units can be located up to 300 from the twinning kit