Got a few of these some 5 or 6 months ago, as I was desperate to find a way to save as much space as possible.
Well, this little guys, head to head take only 2 centimeters, and only if put head to head so jack against jack, otherwise even less.
If like me you have mixed pedals with jack in/outs on the side and/or on the top, then the space goes down to 1 centimeter, or none at all.
Great construction, great quality of sound, simply love them.
The only minus point, in general, is that they don't go above 30 centimeters in length. You've only got 10, 20 and 30.
For the rest, if you need patch cables, just buy these, forget everything else!!!