COSRX Acne Pimple Master Patch is a hydrocolloid dressing that effectively treats acne overnight. Each pack contains 24 patches in 3 different sizes that create a protective barrier, absorb impurities, and maintain skin moisture while promoting faster healing of blemishes. The patches come in 3 convenient sizes: 7mm (10 patches), 10mm (5 patches), and 12mm (9 patches). They feature A.D.F. Hydrocolloid technology that provides three main skin benefits: acts as a protective cover, maintains non-drying properties, and absorbs impurities and oil. The patches should be applied on clean, dry skin and can be worn overnight or during the day for optimal results.