These are custom made ribbon cables for connecting the GCC mainboard to the C-stick daughterboard. They are sturdy and very easy to solder. They come pre-stripped, with the stripped ends still kept on the wire ends to protect them from being bent during shipping.
The 4-pin version is perfectly suitable for all original Gamecube controller mainboards as well as Goomwave and Phob 1.X (for example 1.2.3) mainboards.
The 6-pin version (also available in my store) is made specifically for PhobGCC 2.0, where 6 pins are used for the connection. It's also a bit shorter, as the cable doesn't need to be bent to the side with the 2.0 alignment.
Material: stranded copper with solid tin layer. Can be bent several times, more robust than stock ribbon cables. PVC enamel.
Batch pricing is available here (automatically adjusts depending on the quantity you put in your cart).