So this basically shrinks the color molecules so you can wash the away I warn you now it's a bit stinky but not terrible. I used the extra strength so you leave it for an hour I heated my head with a hair dryer covered it in cling film and made sure it was kept warm. So when the hour was up you have to do lots of rinsing and buffering (TIP:make sure you rinse well or it will re oxidise and go back dark) so when that was all done this is the result.
Check out there website http://www.colourb4.com/ you can buy it from boots, superdrug and some supermarkets there is a full list on the website it ranges in price from around £7 to £12.