Helps earbuds stay in users ears better even during extreme activity designed to fit most ears compatible with flat-faced earbuds 15mm - 20mm in dia adapter stretches & conforms around earbud for a secure fit closely spaced fins flex & conform to ear to help prevent earbuds from slipping out provides superior sound isolation big bass & volume boost twin cone core channels sound waves unimpeded inside users ear canals includes 2 sizes of adapters & carrying pouch white