A head lice comb, also called a nit comb, is used to remove the eggs or nits laid by head lice. Due to the tiny size of the nit, or louse egg, a special comb is required to effectively remove the nits from the hair follicle. The best head lice combs have metal teeth spaced no more than 100 microns (.00394 inches) apart and are securely mounted. Head lice combs with plastic teeth have been shown to be much less effective than head lice combs with metal teeth.