2 in 1 eyelash extension bond and seal design, bond and seal lash glue can linger for up to 72 hours. The ingredients of lash bond glue are safe and gentle. One side is bond, it has a tiny spiral brush head to help apply glue more evenly and is as simple to use as mascara. The other side is lock, it helps form a protective layer after wearing plume individual lashes, locks beauty in your eyes, and makes the lashes maintain a longer retention.