1-2-3 Lice Elimination System. Includes 1 comb. Shampoo & conditioner in one. No. 1 Lice killing brand. Nothing proven more effective. Works fast to kill lice and eggs. Helps children return to school nit free. Rid Lice Killing Shampoo will kill lice completely without leaving a chemical residue. To help prevent reinfestation, use it twice (Day 1 and Day 10). The patented RID comb is proven 100% effective as demonstrated in laboratory studies performed by trained testers. Individual results may vary.