$3.80
Heltec 4S Balancer Box
37 in stock
Weight : 5 Ounce
Size: 2.6*1.9*1 In
https://srikobatteries.com/product/heltec-4s-balancer-box/
Ordered two, and one broke within a few days of testing. Obviously this reduces my confidence in the product, however one is still working. Not the most robust product, but if you're careful, it may be helpful to keep your batteries evenly charged.
easy to use , works great
It done gave up