This is the Astro Flight "Blinky" Balancer for Thunder Power Batteries.
This Battery Balancer is designed for use with LiPo batteries
Accepts one to five cell Thunder Power, Apex and other battery packs with 2mm connectors
One Astro Flight "Blinky" balancer for Thunder Power batteries and one instruction sheet
Length: 1.06" (27mm)
Width: .70" (18mm)
Height: .19" (5mm)