This is the Junsi Electronics Multi-Adapter Balancer Board for the iCharger 3010B, 208B and 1010B+ Balance Chargers. This adapter allows you to balance from 2S to 10S batteries via one harness. Great adapter when you have packs with different cell counts. Eliminates the need to purchase individual harnesses for each battery type.
This board is also designed to allow you to balance multiple batteries at once, as you can charge and balance one 6S battery, two 5S batteries, two 4S batteries, three 3S batteries or three 2S batteries at once on a 10 cell charger. When you connect multiple batteries, the batteries also need to be connected together with a serial charge lead. You should also make sure all the batteries are discharged or used in the same groups that you charge them in (ie: two 5S batteries used in series for a 10S battery pack etc).