They are flat convex glass lenses for 532nm green lasers！
This laser lens is a high permeability optical component used for as Industrial testament, Lab, DIY. Especially for the green laser pointer, laser flashlight and low-power green laser module.
Get a clearer laser effect than plastic lens!
Output Power: None
Dimensions diameter: 6mm
Lens Material: Glass
2pcs/5pcs/10pcs 6mm Glass Optical Lens Flat Convex Mirror for 532nm Green Lasers Pointers