Bought a bunch of these for use on the Mikrokopter ESCs', but ended up with way more than I need. These are Panasonic EEU-FM1E221, OEM on MK BL-CTRL's.
http://www.digikey.com/product-detail/en/EEU-FM1E221/P12383-ND/613744
When I bought them, shipping was more than the parts. I have 19 of them...