The LK-350-12VT(Multi) is an intelligent power switch for the dash cam.
-When you start your car, it automatically supplies power to the cam.
-When you shut your engine off, it keeps power supplied to the camera for a limited time to allow parking surveillance.
-If the car battery gets drained, cam power is cut to prevent the car battery from going completely dead.
Those are its main features.
The manual is confusing and really poor.
After ignition/accessory key off, there is a programmable timer to allow Parking surveillance; 6/9/12/24/36/48 hours max.; Default time is 12hrs.
The LK-350 connects to your car battery power, but it senses the ignition key (on) via the ACC (ACCessories) wire, and it also monitors car voltage.
The car battery low-voltage cutoff has a programmable threshold, from 11.6 to 12.4V below which camera power is pulled; Default threshold is 12.0V which still leaves enough power to start your car, although Lukas recommends upping it to 12.4V during winter.
Once the LK-350 cuts power to the dash cam, it draws only 0.1mA; There is a slide-switch to manually turn off all power. Useful if you are parked for a very long time (weeks); there is zero drain on the car's battery then.
The unit has a built-in digital voltmeter, showing voltage input and voltage output to the cam, updating only when you keep pressing enter, which is annoying. The display also shows if the unit is in countdown-timer mode, or voltage-monitoring mode.
Since it can pull power on the camera without the camera knowing, there is still a danger of file corruption I think.
If there was a third IGN/ACC wire for the dash cam, you would get better functionality integrating the intelligent power switch in the camera.
I find the unit compact, convenient and useful, but a little overly complicated for what it does. Firmware is unpolished.
Out of the box, connect three wires and cam cable, and it's installed and running.
I've only had it for a few days so still learning about how it does. So my notes here might have mistakes.