I've got blonde highlighted hair with pesky grey root regrowth that can really show their arse about 5 weeks after a half head so I thought I'd give this a go as the root sprays I've used over lockdown etc were a bit chalky. I'm bloody staggered how good this thing is https://joshwoodcolour.com/products/dark-blonde-blending-brush no affiliation with the company just really impressed and wanted to share if you too need to prolong those weeks between salon visits because of time and money!
You put it on damp hair at the roots and I was not convinced it would blend as it looks pretty dark but bloody hell, a blast of the hairdryer seems to work magic. It says it'll last 3 washes, think that's stretching it - I've reapplied after each wash.