ZWO 2.8mm - 12mm f/1.4 CS Lens
ZWO 2.8mm - 12mm Wide Angle CS-Mount Lens
This ZWO 2.8mm - 12mm f/1.4 zoom fisheye lens is designed to be used with ASI cameras that have a 1/3" sensor, such as the ASI120. It would allow you to capture a wide swath of sky (approximately 100-degrees) for meteor showers, Milky Way shots, etc.
In order to attach this lens to your ZWO ASI camera, you will also need the ZWO T2-CS or M4CS Adapter.