Wella Professional Welloxon Perfect 12% 40 Vol Creme Developer - 1000ml Wella's classic Welloxon Perfect developer helps to ensure the most accurate hair colour possible for when dyeing your hair at home. Available in a variety of volumes, the welloxon has been specifically reformulated to achieve the best results on all hair types. This 12% Developer will provide up to high levels of lifting. This developer also promises an easy colouring experience possible as it creates an easy and fast mixing formula.