The new DN300 battery features the same waterproof design that Di2 users have loved for generations. Now with 3 ports, it delivers stable power to Shimano's 12-speed road derailleurs and shifters (if a fully wired option is selected). With the same size as its predecessor, the slim DN300 battery can be housed inside seat posts or frames ensuring a clean aesthetic. Now with 3 ports, the DN300 simplifies wiring to front and rear derailleurs, supplying stable power at all times. The third port is for riders who seek the redundancy of Shimano's 12-speed Di2 wired option.The power house of Shimano Di2 is a long-life 7.4V Li-Ion battery that is both compact and reliable, taking shifting effort away from youExcellent sealing and reliability have been proven through repeated field tests in various riding conditions, including extreme temperatures, rain, mud, and cobble stone roadsThe use of a single small and discreet internal battery is light weight, efficient and creates a robust and reliabl