Come in very handy for making your own simple plugable sewable connections. Though hopefully with time these will be replaced with more sewable alternatives, for now they are an okay solution. It is nice to get the break-away option, as this saves time cutting them with the knife and losing the ones in between.

They come in different sizes (streight and angled), the standard spacing is 2.5mm, which is also the spacing on perfboards. The xbee modules have 2.0mm spaced male headers, which require the equivalent females and a breakout board, since they can’t fit the regular perfboard.