What makes selection of hair extensions such a difficult job is the range on offer – hair extensions are available in a variety of colors, lengths, textures and application styles. Even when you decide to go in for fusion extensions, you still need to choose whether you want I-tipped or U-tipped fusion extensions. The major difference in I- and U-tipped fusion extensions is in the method of application. While U-tipped fusion extensions require application of heat for installing the hair extensions, I-tipped fusion extensions are generally cold-fused to the natural hair. The heating tools in U-tipped fusion extensions are used to melt the keratin and come in contact with the natural hair for just a few seconds. For some hair types, even this can be disastrous. For such people, I-tipped fusion extensions are a better option. However, U-tipped fusion extensions have a more even distribution of the sealant. As a general rule, I-tipped fusion extensions are preferable for those with curly or coarse natural hair, while U-tipped fusion extensions are for thin and silky natural hair. However, the final decision rests with you and your stylist.