Interplak by Conair Rechargeable Power Toothbrush Replacement Brush Heads fits Interplak Model NT11. Dentists recommend replacing your brush head every 3 to 4 months. Get triple-action clean with individually counter-rotating tufts. The brush head cleans between teeth, polishes tooth surfaces and gently massages gums. It applies counter-rotational brush head cleaning action for superior results. Includes 2 replacement heads.