They are always cylindrical but comes in different sizes.
Round end power cable.
Unielec uc 225 up 117 e65714 10a 125v 2 prong square round power cable cord nispt 2 2x18awg 0 824mm2 iec60320 c7 black white 6ft 4 1 out of 5 stars 8 9 09 9.
Many americans will have a drawer brimming with such coaxial vexations.
We stock 2 and 3 conductor ac line cords hospital grade power cords multi outlet extension power cords notebook power cords power cord splitters y cables iec and even international cords.
Round cables only require fillers and tapes to ensure concentricity.
Have you noticed that some power supply cables especially new ones like your laptop power cable has a small cylindrical thing near the pin.
In a typical computer system found in a home or office you normally see these bumps on the mouse keyboard and monitor cables.
The purposeless connector or power cable from an obsolete electronic device.
You can also find them on power supply wires when a device like a printer or scanner uses an external transformer.
Lengths vary from 3 to 15 long.
These bumps are called ferrite beads or sometimes ferrite chokes their goal in life is to reduce emi electromagnetic interference and rfi radio.