2 PACK Boka Sensitive Smile Teeth Whitening Strips.32 STRIPS EACH EXP : 3/26 Boka Sensitive Smile Teeth Whitening Strips are designed for sensitive teeth and are intended to be safe for enamel. They are peroxide-free and contain Phthalimido-Peroxy-Caproic Acid (PAP) and Nano Hydroxyapatite (N-HA). Some say they are comfortable to wear and offer effective results with minimal sensitivity. However, others may experience minor teeth sensitivity after a few uses.