Family Size: Lice Easy Pre-Shampoo Oil is a soothing and smoothing oil designed to be used in your lice removal process. After applying 80 mL to roots and scalp area, spread oil with a comb towards tips of hair. (You may use the Lice Grippy Comb to remove dead lice and nits)Leave the oil inhair for at least 15 minutes before washing and conditioning.16 oz size covers 1-4 heads (use every week for three weeks to kill lice and nits)