Here’s a pic of a full cap. For newbies a full cap is a unit that covers the entire head. That includes the nape of the neck, sideburns, back and sides. That’s different than guys with male pattern baldness that lose their hair just on the top of their heads---they still have their own hair on the back and sides. They order a topper and blend the hair system with their own hair. A full cap does have it’s advantages--you don’t have the blend the color or the density with your own hair.