I have a few strands here and there that need concealing, so this was a really interesting product to try as someone who doesn't need to cover all of their roots.
I often don't bother with full coverage products anymore as they cover way more than I need now that I've changed my hair colour. But this product I would definitely bother with for those few strands that need touching up or concealing.
The product comes in a mascara-like tube with a mascara-like wand. But it does feel harder and rougher than a mascara wand.
To use on individual strands, I didn't find the wand that effective, so I ended up covering all my roots to conceal a few strands. But what this did show me is that the colour didn't rub off on my clothes or pillow. It did make the hair feel slightly straw-like, but a lot less so than some of the sprays feel. You also had more control than with a spray.
I then tried putting some product on my finger and rubbing it along the offending strands. I found this really effective and more economical. It was also easy to wash off.
I found this product really great for those small touch ups. For the few strands that got missed during a colour or the couple of grey hairs that don't seem worth dyeing your whole head for. This is perfect.
I can see me keeping this product on hand for many years to come.