Molex PicoBlade 2-pin Cable - 200mm
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When 0.1" is too big, and JST PH's too chunky, the ultra-slim "PicoBlade" is a reliable alternative. These are only 1.25mm pitch, but have a nice clicky connection.
This cable is nice and long, 200mm in fact. It's got both small form factor (won't take up a lot of real estate on your PCB) and friction lock to make easy-breezy connections to your HalloWing or anything else with a 1.25mm PicoBlade connection.