Product Description Developer for precision and ease of application with less swelling. Contains hydrogen peroxide and flexible acrylic polymers. Couture Colour Service. Developer for precision and ease of application with less swelling Contains hydrogen peroxide and flexible acrylic polymers Available in vol. 20 – 6% (for gentle lift), vol. 30 – 9% (extra lift), vol. 40 – 12% (maximum lift) Couture Colour Service