Overall, micro ring extensions are currently considered the safest types of hair extension. There is no glue being added, and chemicals are not required to remove them as you would with glued-in extensions. Tiny copper rings are used to combine strands of natural hair with the hair extension. Also known as micro bead or micro loop extensions, they are a really great choice when it comes to a longer-term hair extension solution. The hair extensions are applied one strand at a time with the rings holding the extensions in place securely. No glues or chemicals are required. Hair extensions using the micro ring technique last for around 3 to 4 months before maintenance is required and hair as short as 4 inches long can be extended with this method.