Useful for checking things like bank notes. By shining the light on the top centre of one side of the note (there used to be more spots to check on the older notes), a "20" in different colours appear that helps prove a note is genuine. There may be other uses.

Still working fine, just not needed now.

USB shown for scale and is not included.

I can post this for free, and arguably I'd prefer that anyway as I can post at my own leisure, but to collect:

COLLECTION TIMES from Woolwich (1 min walk from DLR station):

15/07: Any time until 23:00
16/07: 15:00 to 16:00 but may be available later if plans change
17/07: Unavailable
18/07: Unavailable
19/07: 12:00 to 16:00
Then very low availability due to shift work

Keychain UV light (with free post) (Woolwich SE18)