WIG AND HAIR UNIT SPECIFICATIONS Specifications are the different categories for your wig or hair unit that tell us how to design and make it to fit your head, ideally like a glove. Since correct head measurements are the most important specifications for your custom wig or hair unit, you want to make sure to follow the illustrated guides carefully. Simply select the guide for which wig or hair unit you are ordering. Follow the written instructions while placing the measuring tapes on your head as illustrated on the model. IMPORTANT: Before taking your head measurements, press your hair as close to your head as possible by either braiding or wrapping it, then cover with a wig cap to get the most accurate results. It is a good idea to take the measurements 3 or 4 times to become familiar with the process. Additional specifications for wigs and hair units are given below. Please click each link to learn more about them. HAIR ORIGINS & TEXTURES HAIR COLORS HAIR DENSITY CAP DESIGNS.HAIRLINES.BLEACH KNOTS LACE COLORS (click on head measuring chart for closeup view)