The single cell module BEGIN is designed to be installed on first cell of the battery pack. It is followed by cells with single modules. Last cell has installed END module.
This cell module is included in 12V set of BMS123 Smart
Check the GWL/Power BMS123 Smart product line.
GWL/Power BMS123 Smart is the latest innovative solution for the lithium cell and battery pack monitoring and management, specifically designed for use in solar projects and energy storage application. GWL/Power Smart BMS is a complete system for working with LiFePO4 and LiFeYPO4 cells and batteries.
Simple installation, easy settings, easy and reliable operation.
Concerning the GWL/Power BMS123 Smart system please study all available details here: http://gwl-power.tumblr.com/tagged/BMS123Smart
GWL/Power BMS123 Smart solution uses the GWL/GreenEye Technology for Smart Monitoring over the Bluetooth Battery communication protocol.