Pack of 27 patches include 9x Pink, 9 x Blue, 9 x Olive Using our Grid-Relief Technology, our Itch Relief patches mechanically lift the skin (no chemicals) to drain the lymphatic system which has been injected by the mosquito's saliva that causes the itch. Our Itch Relief Patches contain no chemicals. They work kinesthetically! Our Itch Relief Patches will start working in 30-60 seconds to relieve the itch, and can last for up to 7 days (and are completely waterproof)