The safe & sound nit comb can be effective in detecting the presence of head lice and can be used in the wet combing method of treatment. For chemical treatment using ringes or lotions it is recommended that the advice for prefered local healthcare professional is sought. Head lice are small insects relughly the size of a match head when fully grown and usually grey or brown in colour the eggs are laid in sacs known as nits stuck to the base of individual hairs and are dull in colourThe eggs take 7-10 days to hatch and the empty sacs being white and shiny may be found further along the hair as the hair grows out. The lice take 7-14 days to reach maturity wherelupon reproduction can take place.