Guidance for measuring the base/cap for Prestige U part extensions.
Using a soft tape measure (can't find one? How about a ruler and a piece of string?)
Measure the two most important parts of your head. Front (hairline) to nape (top of neck). That's measurement one.
Then ear to ear round back of head, from top of ear to top of ear going via the widest part of your head.
Then take an inch off each measurement to allow for blending with your bio hair.
Example, you measure:
Front to nape - 13 inches
Ear to ear - 13 inches.
Take an inch off each and you have a 12x12 cap, size small.
Caps have stretch edges and adjustable straps so you can be sure of a snug fit.
Keep in mind the length of hair is measured top to bottom, so from crown to tips, same way as a wig is measured.
E.g a 22 inch U part extension will be similar to 18 inch clip ins.