Straight Female Headers

They work well, but keep in mind that you will loose some pins when you cut them

They are described as 'breakable' and I thought break into 2 x 20pin, but further reading of small print on Robot Shop web site says you might lose a few pins in process of snipping with wire cutters.

these break away headers are perfect for attaching an arduino to your proto board. nice solid connections that almost feel permanent.

Nice solid connections. It was only a little difficult to break off the segments

Great solid fitting when you plug a wire into it, but I had difficulty snapping off the individual segments. Tried with my hands, tried with a vice, tried with needle nose pliers but they always broke. For every individual segment I managed to break off intact, I lose 2 from cracking and an uneven break.