10x Lifting SerumsNot for home use. Patch test required. Professional use ONLY. By purchasing you are confirming you are certified to do the treatment.Fine or weak hair Serum 1 - 8 minutes Serum 2 - 4 minutes Regular hair Serum 1 - 10 minutes Serum 2 - 5 minutes Strong hair Serum 1 - 12 minutes Serum 2 - 6 minutes