One variation on the standard wefted cap construction is the capless wig cap. The "capless" is not really "capless", but the wefts are less dense and have a bit more space between them. This provides a lighter weight cap with better air circulation. Many women who wear wigs for medial reasons prefer a capless construction. Because they will more likely wear their wig for longer periods of time, a lighter weight cap provides more comfort.
Capless wigs are usually secured with tape, medical adhesive, and/or clips, although new advancements in stretch technology now allows some cap constructions with thin resilient dual elastic sides that provides comfort and a precise all day fit. Many capless wigs will have adjustment straps at the nape (back neck area) to allow the wig to be sized down for a more snug fit.