The LDR ZX-LDR is a low cost module designed to measure ambient light intensity.
It works using an internal Light Dependent Resistor (LDR) that varies its value based on ambient light.
It has analog output (0 to 5 Volt) that can be read from any microcontroller or Arduino thanks to a resistor connected in series to the LDR.
It has a 3 pin JST connector (voltage, signal and ground) that enables it to be installed easily on robotic projects or development boards.
This particular sensor has 2 JST outputs one negative and one positive the first one will return a negative voltage when exposed to light and the second one will return 0V.