This 2 Core Transparent Flat PVC Clear Flex 0.75mm has a transparent out and inner sheath so easier to hide if you don't want to see the flex as the main feature of a light.
One of the cores has a very small Blue tracer cotton to identify the core when it come to wiring. Please make sure that the live conductor (which ever one you choose) is switched with the in line on/off switch if you have one and also goes to the pin that makes with the centre of the Edison Screw lamp if using this type of bulb.
Sold per metre so if you order 3, you will get 3m in one length.
This flex is 5.7mm across the flat.