Gray or Black
Regular generic computer power cable. All are approx 5-7' long. All are 3 prong - they have a ground pin for U.S. outlets. Cables are gray or black in color.
A cable is free by request with any computer, monitor, external hard drive or printer purchase if you need one. You may already have a pile of them, and they do add to the shipping weight.
Apple branded power cables are very rare, but one turns up now and then. I'll add then as I come across them.