Eyelash extensions single these eyelashes are placed onto the lashes to make the lashes longer these lashes give a more natural look you will need to get these infilled every 2 4 weeks depending on how well you look after them and how you sleep eyelash extensions clusters these eyelashes are placed onto the lashes in groups of 5 lashes these lashes give a fuller look you would have these lashes done if you like the fuller look or would like them for an occassion express eyela