Hairpieces that have openings at the base through which the client's hair is blended are referred to as:

Hairpieces that have openings at the base through which the client's hair is blended are known as integration pieces. This type of hairpiece is designed specifically to allow the wearer's natural hair to flow through the openings, creating a more seamless and natural look by integrating with the client's own hair. This design enhances volume and length without completely covering the natural hair, making it a versatile option for those looking to add aesthetic value to their hairstyles.

While wiglets, switches, and cascades are all types of hairpieces, they do not feature the same design characteristic as integrative pieces. Wiglets are smaller hairpieces typically used to add volume or style but do not have the open base for blending. Switches are often used for accentuating or styling but do not incorporate the client's hair in the same way. Cascades are generally designed for a specific type of look or style without the blending capability that integration pieces offer.