If you're looking for an upgrade lipo battery for your Radiomaster TX16S, Spektrum DX7/DX8 or DX9 then look no further. 4000mah capacity will increase your runtime over 18650 (radiomaster) cells or nimh (spektrum) options and can be used with your regular chargers. Designed to fit nicely into the battery compartment of Spektrum DX7S/ DX8/ DX9 and Radiomaster TX16S (2nd gen or newer). For Spektrum, just remove the foam padding that comes with the stock nimh battery and set your Spektrum DX7/DX8/DX9 radio to lithium polymer battery mode. For Radiomaster, just install the battery and adjust your low voltage alarm setting (6.8v) and voltage ranges (6.4-8.4v recommended).
*** This battery comes with a protection circuit board (PCB) that will cut the power in case any cell voltage drops below 2.8V to protect the cell. It helps when you forget to turn the radio off and the radio tries to drain all the power of the battery. The PCB will also restrict the charge to 4.2V max to prevent any overcharge.
*** This pack is recommended to use for the radio transmitters only, not as a receiver battery.