The module provides your Arduino or others MCU with the capability to communication to CAN Bus, such as hacking your vehicle. CAN Bus is a common industrial bus because of its long travel distance, medium communication speed and high reliability.
It is based on MCP2551 and MCP2515, which can provide speed up to 1Mb/s.
The Module is a cheaper version of Serial CAN Bus Module, the difference is the MCU on-board. Lite version user a cheaper STM8S MCU while there's Atmega168PA in the Serial CAN Bus Module. The 2 modules shares the same AT command and usage.
If you need to program the AVR mcu with Arduino IDE, please take Serial CAN Bus module, otherwise, the Lite version is good enough.