There are three common types of nasal spray devices: unit-dose, bi-dose, and multi-dose. A unit-dose device is for single-use, pre-filled, already-assembled, disposable products such as NARCAN (naloxone nasal spray) and IMITREX (sumatriptan nasal spray). It is ideal for urgent use treatments. A bi-dose device is described above. A multi-dose device is ideal for chronic-use medicines such as FLONASE. Each device is already-assembled and pre-filled with many doses for an extended period of use (e.g., a month, season). It should be discarded after it is empty.