A 100% free of formaldehyde and its varients ensure bio kertain an absolute safe soft straightening with the benefit of kertain supplyment bio kertain ensure a rich supplement even to the hair made under unique technology which help boi kertain application on hair make soft straightning to enrichquickly the supply of neutriant and moisture to the entire hair, there by keep the hair straind by straind,soft,smooth,tangle free lustrous and glossy hair.