Thickness: 1.5mm/2mm
Diameter: 18/20/20.5/21.8/28/41.5mm

Size:
18mm x1.5mm
20mm x1.5mm
20.5 x 2mm for Convoy S2/S2+/S3/S6/S9 BD03 Flashlight
21.8 x 2mm
28 x 1.5mm for 501B 502B Flashlight
41.5 x 2.0mm for C8 C8+ C12 Flashlight

Feature:
Ultraviolet light filters,
It needs to be used with 365nm UVlamp.
Blocking other light except 365nm UV