The connectors have the exact size to connect Sanwa and Seimitsu buttons. No more soldering and the perfect way to make your joystick or arcade flexible. The best way to firmly connect these connectors is to use flat plyers to squeeze the connector a bit before connecting them. If you do that prior to connecting them, they will snap into place and need a lot more force to disconnect.
For a standard stick including Start/Select and 8 buttons you'll need at least 20 connectors.