Short answer: keratin bond extensions are applied strand by strand. Each extension strand has a small keratin point that is professionally worked to connect it to a proportionate section of natural hair.
The technical advantage of the system is not simply having a “small” attachment: it is the ability to distribute the material across many separate points and adapt position and quantity to different areas of the head.
How is the weight distributed?
Each small strand adds a limited amount of hair and forms part of the overall design. With VELVET Fusion, for example, the strands are around 1 g each and the line is available in different total quantities. This makes it possible to build the blend without concentrating all the weight into a single structure.
The total weight must still be compatible with the density and strength of the natural base. A small attachment applied to a section that is too weak does not become gentle simply because it is small.
How is the keratin attached?
During professional application, the keratin point is made workable with the tool intended for the system and shaped around the natural hair section. Once stabilised, it forms a compact attachment that moves down as the natural hair grows.
During everyday styling, hot tools such as straighteners and curling irons should be used on the lengths without concentrating heat directly on the keratin point. See Can you use hair straighteners on human hair extensions?.
What happens as the hair grows?
As the natural hair grows, the application point moves down. The strands remain attached, but their position changes progressively. The organisation of the regrowth, naturally shed hairs retained around the attachment and the condition of the strands therefore need to be monitored over time.
Overall wear time should not be confused with maintenance. We cover the two separately in How long do human hair extensions last? and How often do extensions need maintenance?.
How are they removed?
Removal should be professional. The keratin point is treated using the appropriate procedure and separated without pulling out the natural section. Tugging, breaking or trying to slide the attachment off is exactly the sort of shortcut that can turn a good system into a problem.
In summary
Keratin bonds are a strand-by-strand system that allows highly precise distribution of weight and attachment points. The result still depends on the quality of the design, the proportion between extension and natural hair, and correct application, maintenance and removal.