There are basically two types of wigs cap constructions that are the most popular.

1) The most common is the “Wefted Cap.” The vast majority are also known as "capless" wigs. They are constructed from rows of wefts (fringes) of synthetic fiber or human hair that have been sewn together into the shape of a cap, but do not have an underlying solid cap, per se. The more expensive wefted wigs feature a lace inset at the crown which allows the wearer to part the wig and brush the strands in any direction.

"Thin wefted" wig will usually have the rows of wefts spaced farther apart, which makes the wig lighter and more "breathable." A thin wefted wig will often lack the lace inset at the crown. The downside of this is that sometimes the underlying wefting can be seen when the wig is parted on top. An extreme example of thin wefting is a costume wig which can have wefts spaced very far apart, sometimes to the point that the wearer's own hair will show through.

Although becoming less and less popular, some wefted wigs still feature "crimp wefting" or "perma-tease" at the crown. This is the "fuzzy" looking hair that sometimes sticks up at the top of a wig. It is designed to make the wig look fuller (which is RARELY necessary unless you like the "big hair" look). This matt of short, frizzy hairs will also tend to hide the underlying cap construction, which is seen by wig manufacturers as a good thing.

In extremely cheap wigs, as well as many costume wigs, there will be a heavy net cap showing when the wig is turned inside out. These are still classified as “wefted” wigs, but are NOT considered “capless” wigs. This netting is considered to be an outdated form of cap construction, and is rarely seen in a fashion wig made within the last ten years.

All wigs will have adjustment straps at the nape (back neck area) to allow the wig to be sized down for a more snug fit. Generally, these straps will have Velcro attachments, but will sometimes feature hooks that fit into tiny adjustment pockets. Either system works well, and both are used on inexpensive as well as expensive wigs.

2) The second most common cap construction is the “Monofilament-Top.” This is a wefted wig that features an inset of transparent micro-mesh sewn in at the crown, with the individual strands of synthetic fiber or human hair hand-tied into the mesh. Mono-top wigs are generally more natural-looking, as the hair appears to be growing out of a real scalp, and there is no "crimp wefting" to make the wig look artificially full.

This type of cap was first developed for women who had experienced significant hair loss due to chemotherapy, alopecia, or other medical reasons, as the transparent mesh allowed the bare scalp to show through. You may sometimes see mono-top wigs referred to as "medical wigs" for this reason. However, many women with full heads of hair prefer the mono-top wigs for their superior natural appearance. With a mono-top wig, the hair can be more sharply parted on either side of the head than with a conventional wefted cap wig.

All mono-top wigs feature "tape tabs" on the inside of the cap, usually in 4 or 5 spots. These tabs are made of a shiny plastic material, and allow the wearer to use double-sided tape to secure the wig to the head, if necessary. Generally, mono-top wigs are recognized as a higher quality wig product, and are more expensive than standard wefted cap wigs. A slightly less expensive alternative is a wig featuring a monofilament part, rather than a full monofilament top. These are wigs that have a thin strip of monofilament mesh sewn in just at the left, right, or center part line. In these cases, the location of the part CANNOT be changed.

3) A “Fall” or “3/4 Cap Wig” is designed to be worn with the wearer’s own hair showing at the front hairline and down the temples to the ears. Most falls utilize conventional wefted caps. They are attached using a half-round comb at the front (bangs area) and another at the back (nape area) for an extremely secure fit. Some falls feature a cloth headband (almost always black) which affords a slight separation between the color of the fall, and the color of the wearer’s own hair, which can be beneficial when these colors don’t match exactly.

4) Probably the least common type of cap construction is the “Hand-tied.” A 100% hand-tied wig usually starts at $500.00 for a synthetic style, and can get into the $1,000’s for human hair versions. This is due to the labor-intensive nature of making the wig. It takes a worker one full day to completely hand-tie a wig, and after this, the wig still needs to be hand cut and styled. The cap of a 100% hand-tied wig is extremely stretchy, very similar to a nylon stocking. To keep costs down, some manufacturers offer wigs that are hand-tied at the front hairline and/or crown only. There are a few wiglets available in hand-tied versions, as well.