The addition of silicone offers a slight protection barrier against chemical reactions between products and PH imbalances. The silicone also acts a heat protectant and UV protectant. We infuse our dyes with silicone, so when we color our hair extensions, the silicone is deposited into the hairs cortex simultaneously. We do not coat the hair with silicone. The infused silicone will result in a slight sheen to the hair as opposed to extensions without silicone. Silicone also helps minimize tangling. The hair without the infused silicone looks more natural, but you will have to be more mindful of the product and acitvities you do while wearing your extensions. When using extensions without the infused silicone, you must use the RemySoft MoistureLab 3-step system to prevent the extensions from drying out.