These are nifty, about half-inch disks that glow in the dark. They go out of stock as fast they are put in inventory, so if you want some, act now.
UGM Mini Markers - Pack Of 10 | CountyComm – CountyComm
Here's a crappy cell phone pic of the last pack of them I bought, these have been exposed to about a ten second shot of very bright tac light.
They retain a glow all night, with normal room light. I have one on my hand-held amateur radios, and the ear pro and flashlight on my nightstand.
They also have larger bars that would be suitable to attach to luggage, not currently on sale.