Licensed colorists who still offer the cap-highlighting technique, or students learning it. It's a technique-specific tool: if you're not doing cap highlights, you won't have a use for it.

It's purpose-built for cap highlighting specifically — the different hook gauges are what let you control how much hair comes through the cap at each pull.

• Fit the perforated highlighting cap snugly on the client's head
• Choose a hook size based on the highlight density you want
• Insert the hook through a cap hole and draw a section of hair through
• Apply lightener or color to the pulled-through strands only
• Repeat across the cap, leaving the rest of the hair protected underneath

• Three gauges give real control over highlight density, from subtle to heavy
• Keeps the rest of the hair protected from lightener while you work
• Stainless steel holds up to repeated use and cleaning

Cap highlighting itself is slower than foiling for large sections, and it's genuinely impractical on long or very thick hair — the technique, not the tool, sets that limit.